SC400 OBD-I to OBD-II conversion project in progress... :(
04-11-11, 02:02 AM
#1
SC400 OBD-I to OBD-II conversion project in progress... :(
Yes, you read it right, let's drop an OBD-II 1UZ-FE into an OBD-I SC400 car.
Why would you do that and how's that working out for you so far, you might ask? Read on and find out...
Dates and basic progress details are noted in post entries as I go, and they begin below the overly frivilous detail filled project introduction below.
P.S. If anyone can tell me what model year of SC400 a P/N 89661-24453 ECU is out of and verify for sure if that model year had the key-specific Lexus "Immobilizer" system or not, that would be greatly appreciated!!!
Here we go!
So a buddy bought a pretty clean and good looking SC400 a couple weeks ago really cheap with nice paint and good interior with near perfect leather and "new engine" but the car's NOT running...
Turns out it's a 1993 OBD-I car with an unknown model year but supposedly bought together as a complete matched set of OBD-II Engine, Tranny, Engine Harness, and ECU that have all been dropped into this OBD-I chassis. They were supposedly "mostly installed" to the point that it actually cranks normally when you connect the battery and turn the key but it doesn't even sputter or hickup or show any signs of ignition at all. The previous owner and whoever was helping him tried for a while to make it work but it just wouldn't start and they couldn't get spark or make the fuel pump to run no matter what they tried so he eventually gave up and sold the car dirt cheap "as-is, NOT running".
He apparently didn't realize the engine, harness, etc wasn't OBD-I when he bought them for the car or maybe didn't realize it made a difference. But at some point when the plugs weren't entirely matching up he became suspicious that the whole setup might be OBD-II and therefore incompatible with the OBD-I car, especially when he couldn't get the fuel pump to run at all no matter what they tried.
Oh, and the OBD-II engine, harness, ECU, and tranny are from a TRAC equipped SC400 and this particular 1993 chassis it's now in is a NON-TRAC car, just to complicate things a little more...
I took one look at the car as we talked with the seller before my buddy bought it and in a matter of seconds I determined that it was almost definitely an "OBD-II problem" in the OBD-I car.
The give-away that told me so was that the Diagnostic connector in the engine bay looks EXACTLY the same and has all the same pin labellings in the cap in both versions, BUT the OBD-II version of that connector is missing most of those pins and usually doesn't have any of that connector anti-corrosion grease in the pin holes like the OBD-I cars normally have in their Diagnostic connector.
Ironically, one of the pins that's missing from the OBD-II diagnostic block is the FP pin, (Fuel Pump) so the car's previous owner couldn't do the usual quick and simple FP to B+ fuel pump jumper test, DOH!
I learned about the differences in that connector 3 years ago with my old beater 96 Camry, a final year Gen3 that was also the first year of the OBD-II equipped Camry. The Camry had developed what appeared to be a fuel pump problem that I discovered I couldn't actually test for in the usual way because the label in the diagnostic connector cap said the FP pin was there but there wasn't any actual pin in the connector or any wire in that part of the harness for it at all... Who knew a Camry fuel pump problem would prove to be so useful a few years later?
So I've been "volunteered" to make this project car work, yay...
and I'm NOT an auto mechanic at all, I'm just pretty good at tinkering...
This is the ongoing story of the "fun" that can often happen when you inherit someone else's unfinished project car... and of course the best part is that it's NOT even MY car!!!
So far it's a lot less "complete" (finished) than we thought as far as the mechanical installation goes but it seems like all the necessary parts appear to have been included my buddy put most of the interior back together already and this project is looking a lot more promising as I continue my investigation and I keep making very good progress at a much quicker pace than I expected, and time will tell and I'll post the progress as I continue the work.
We decided that the repair path choices to fix this car were to either find the right year of engine, harness, and ECU for this model year and do a whole swap again so it would all just plug right in and work (in theory), or find an OBD-I harness and ECU and sensors and such and try to convert the engine over to match the car's year and its' original wiring and hope that would work, or try to make the complete matched OBD-II "set" that's already pretty much physically installed work in this OBD-I car.
My buddy who actually bought the car would rather go through the physical labor to swap it back to the right year engine, harness, ECU, etc but he's on a time limit and budget limit so I asked why we couldn't just try to make it run as-is instead, silly me... What was I thinking...
So I was given the task to try and make it run as-is while he pursues the option of a swap back to a matched engine, harness, ecu, etc for this model year car and if he finds a complete used OBD-I setup he's happy with before I get it running as-is then we'll go with his solution but even as a total EFI wiring noob I really think I'll win this challenge...
Project begins...
3/31/2011
Viewed the car with my buddy, expressed my opinion that it's totally worth the price in such good cosmetic condition but definitely NOT a quick fix and includes both unknown potential costs and a lot of work to finish the project, so he decided to buy it...
Then spent the next couple days on the phone with him playing the "what if" and "what about this?" game about it...
4/4/2011
Car delivered to my buddy's spare driveway this evening via tow-truck but the weather was HORRIBLE and my cell phone didn't ring when he called and he didn't leave a message so I didn't know the car had arrived until really late that night...
4/5/2011 - 4/6/2011
So far I spent a couple of evenings slowly staring at the car inside and out, all "up close and personal" with it, noting all unplugged and "extra" connectors and finding out what worked and what didn't as-is and replacing and reconnecting unplugged and missing headlights and fixing broken marker lights and such like that.
4/9/2011
Then I spent a day at my local "Pull-A-Part" junkyard looking over the wiring and numerous other things on a 1992 SC400 as a connector reference, which happened to have seat heaters and TRAC which this project car doesn't have but doesn't have Automatic-ON/OFF headlights or a passenger airbag system which our project car does, to my suprise.
*Side note:
While at the junkyard staring at that 92 SC400 I was also successfully able to scavenge an OBD-II Diagnostic "Data Link" check connector with a few inches of cut factory harness wires still on it out of a first-year OBD-II 1996 DX I4 Toyota Camry in hopes of retro-fitting it into our project 1993 SC400.
See the "*Interesting OBD-II tidbit..." in the 4/10/2011 progress notes for further details!
4/10/2011
At this point I've now gone through and found all appropriate mates for all "extra" connectors and plugged just about everything in as far as I know and verified about 80% of fuses and relays as good and replaced a couple of fuses but still have a few to check.
Several of the "extra" connectors were in the OBD-II Engine Harness and turned out to be TRAC and ABS related and I'm not sure if I'll need to deal with them as an extra potential issue or not, time will tell...
I haven't yet done a thorough inspection of engine bay wiring and connections but that's scheduled to happen very soon and I did already do a quick visual plug check with nothing obvious jumping out at me yet.
*Actual progress report...
As of earlier today we now have all proper dash warning lights working finally and a working fuel pump which is a HUGE plus, and a few other things that didn't work at all when I started are working properly now, so we now have working Fuel which the previous owner didn't but still no spark...
At my insistence, althout they were about triple the price I was expecting for each one, the genuine Lexus Electrical Wiring Manuals for the 93 and 97 (pre/non-immobilizer year OBD-II, I THINK?) SC400 have been ordered and are in-route to my buddy's place, scheduled to hopefully arrive one day this week.
In the meantime I've been staring at random incomplete diagrams found online for both years as my only reference source so progress is very slow.
*Interesting OBD-II tidbit...
To my suprise, with a bit more staring at tiny black and white 1996 SC400 wiring schematic sheet I tried to splice that Camry OBD-II diagnostic Data Link Connector into this SC400's new OBD-II engine harness earlier today with "gator clip" jumper wires and some careful temporary open heart surgery to the OBD-II harness near the ECU plugs.
I guess I did it right because my reader powered on and linked up the moment I plugged it into the connector and at first scan we got the all-clear but then I had my buddy turn the key to crank the engine for a few seconds and when he stopped I ran another scan. At that point the reader said the ECU was reporting the P1300 and P1305 codes (iirc) which the manual for the reader says is "Igniter 1 Circuit Malfunction" and "Igniter 2 Circuit Malfunction" for Toyota/Lexus vehicles.
Just for the fun of it I tried to clear the codes, ran another scan, and got the all-clear so that worked too. Then to be sure it was working right we turned the key to crank the engine again and then ran another scan and the P1300 and P1305 codes returned which was great to see and turned out to be VERY helpful!
Based on the OBD-II error codes the ECU reported, after a bit more staring at partial online SC400 wiring diagrams I located and began probing the igniter and coil connectors and found that there is no B+ signal getting to either Igniter or either Coil which explains the ECU's reported "Igniter Circuit Malfunction" codes for sure and points me in a helpful direction to search out and correct the total lack of ignition system power that the OBD-II system revealed and verified for me. I'm assuming it's either something in the engine bay we haven't noticed that didn't get plugged in or a blown fusible link although so far they all meter out with power on both sides or a relay that's not energizing or is possibly missing, or even possibly a connector pin-out discrepancy between the two different ECU systems and model years.
So now I'm trying to determine path and all connectors involved in that power path for an OBD-I car from the fusebox to the OBD-II engine harness to the igniters and coils, hoping that it's not an Immobilizer year OBD-II ECU.
Oh, and I TOTALLY forgot to mention that this car also used to have some sort of fancy aftermarket stereo system and expensive aftermarket alarm installed but the person who sold the car with no engine or transmission to the guy we got it from had also removed his fancy stereo and expensive alarm system and the car hasn't run since. So there's no telling if there's a cut wire or missing relay or added ignition-kill wiring somewhere in a kick-panel that could also be killing the ignition system either.
*Frivilous commentary and other thoughts about the ECU...
I'm slightly concerned about the possibility of the Lexus Immobilizer system because I have absolutely no way of resolving that in this car that doesn't even know what OBD-II is, much less the Immobilizer system, but if I can get the right diagrams with the full connector path info and it really is pre-Immobilizer then I'll be suprised if I don't have this car running within the next few weeks, if not sooner...
More to come as I stare at more wiring diagrams and hunt for the missing ignition system B+ signal and report on my next encounter with this car...
Why would you do that and how's that working out for you so far, you might ask? Read on and find out...
Dates and basic progress details are noted in post entries as I go, and they begin below the overly frivilous detail filled project introduction below.
P.S. If anyone can tell me what model year of SC400 a P/N 89661-24453 ECU is out of and verify for sure if that model year had the key-specific Lexus "Immobilizer" system or not, that would be greatly appreciated!!!
Here we go!
So a buddy bought a pretty clean and good looking SC400 a couple weeks ago really cheap with nice paint and good interior with near perfect leather and "new engine" but the car's NOT running...
Turns out it's a 1993 OBD-I car with an unknown model year but supposedly bought together as a complete matched set of OBD-II Engine, Tranny, Engine Harness, and ECU that have all been dropped into this OBD-I chassis. They were supposedly "mostly installed" to the point that it actually cranks normally when you connect the battery and turn the key but it doesn't even sputter or hickup or show any signs of ignition at all. The previous owner and whoever was helping him tried for a while to make it work but it just wouldn't start and they couldn't get spark or make the fuel pump to run no matter what they tried so he eventually gave up and sold the car dirt cheap "as-is, NOT running".
He apparently didn't realize the engine, harness, etc wasn't OBD-I when he bought them for the car or maybe didn't realize it made a difference. But at some point when the plugs weren't entirely matching up he became suspicious that the whole setup might be OBD-II and therefore incompatible with the OBD-I car, especially when he couldn't get the fuel pump to run at all no matter what they tried.
Oh, and the OBD-II engine, harness, ECU, and tranny are from a TRAC equipped SC400 and this particular 1993 chassis it's now in is a NON-TRAC car, just to complicate things a little more...
I took one look at the car as we talked with the seller before my buddy bought it and in a matter of seconds I determined that it was almost definitely an "OBD-II problem" in the OBD-I car.
The give-away that told me so was that the Diagnostic connector in the engine bay looks EXACTLY the same and has all the same pin labellings in the cap in both versions, BUT the OBD-II version of that connector is missing most of those pins and usually doesn't have any of that connector anti-corrosion grease in the pin holes like the OBD-I cars normally have in their Diagnostic connector.
Ironically, one of the pins that's missing from the OBD-II diagnostic block is the FP pin, (Fuel Pump) so the car's previous owner couldn't do the usual quick and simple FP to B+ fuel pump jumper test, DOH!
I learned about the differences in that connector 3 years ago with my old beater 96 Camry, a final year Gen3 that was also the first year of the OBD-II equipped Camry. The Camry had developed what appeared to be a fuel pump problem that I discovered I couldn't actually test for in the usual way because the label in the diagnostic connector cap said the FP pin was there but there wasn't any actual pin in the connector or any wire in that part of the harness for it at all... Who knew a Camry fuel pump problem would prove to be so useful a few years later?
So I've been "volunteered" to make this project car work, yay...
and I'm NOT an auto mechanic at all, I'm just pretty good at tinkering...
This is the ongoing story of the "fun" that can often happen when you inherit someone else's unfinished project car... and of course the best part is that it's NOT even MY car!!!
So far it's a lot less "complete" (finished) than we thought as far as the mechanical installation goes but it seems like all the necessary parts appear to have been included my buddy put most of the interior back together already and this project is looking a lot more promising as I continue my investigation and I keep making very good progress at a much quicker pace than I expected, and time will tell and I'll post the progress as I continue the work.
We decided that the repair path choices to fix this car were to either find the right year of engine, harness, and ECU for this model year and do a whole swap again so it would all just plug right in and work (in theory), or find an OBD-I harness and ECU and sensors and such and try to convert the engine over to match the car's year and its' original wiring and hope that would work, or try to make the complete matched OBD-II "set" that's already pretty much physically installed work in this OBD-I car.
My buddy who actually bought the car would rather go through the physical labor to swap it back to the right year engine, harness, ECU, etc but he's on a time limit and budget limit so I asked why we couldn't just try to make it run as-is instead, silly me... What was I thinking...
So I was given the task to try and make it run as-is while he pursues the option of a swap back to a matched engine, harness, ecu, etc for this model year car and if he finds a complete used OBD-I setup he's happy with before I get it running as-is then we'll go with his solution but even as a total EFI wiring noob I really think I'll win this challenge...
Project begins...
3/31/2011
Viewed the car with my buddy, expressed my opinion that it's totally worth the price in such good cosmetic condition but definitely NOT a quick fix and includes both unknown potential costs and a lot of work to finish the project, so he decided to buy it...
Then spent the next couple days on the phone with him playing the "what if" and "what about this?" game about it...
4/4/2011
Car delivered to my buddy's spare driveway this evening via tow-truck but the weather was HORRIBLE and my cell phone didn't ring when he called and he didn't leave a message so I didn't know the car had arrived until really late that night...
4/5/2011 - 4/6/2011
So far I spent a couple of evenings slowly staring at the car inside and out, all "up close and personal" with it, noting all unplugged and "extra" connectors and finding out what worked and what didn't as-is and replacing and reconnecting unplugged and missing headlights and fixing broken marker lights and such like that.
4/9/2011
Then I spent a day at my local "Pull-A-Part" junkyard looking over the wiring and numerous other things on a 1992 SC400 as a connector reference, which happened to have seat heaters and TRAC which this project car doesn't have but doesn't have Automatic-ON/OFF headlights or a passenger airbag system which our project car does, to my suprise.
*Side note:
While at the junkyard staring at that 92 SC400 I was also successfully able to scavenge an OBD-II Diagnostic "Data Link" check connector with a few inches of cut factory harness wires still on it out of a first-year OBD-II 1996 DX I4 Toyota Camry in hopes of retro-fitting it into our project 1993 SC400.
See the "*Interesting OBD-II tidbit..." in the 4/10/2011 progress notes for further details!
4/10/2011
At this point I've now gone through and found all appropriate mates for all "extra" connectors and plugged just about everything in as far as I know and verified about 80% of fuses and relays as good and replaced a couple of fuses but still have a few to check.
Several of the "extra" connectors were in the OBD-II Engine Harness and turned out to be TRAC and ABS related and I'm not sure if I'll need to deal with them as an extra potential issue or not, time will tell...
I haven't yet done a thorough inspection of engine bay wiring and connections but that's scheduled to happen very soon and I did already do a quick visual plug check with nothing obvious jumping out at me yet.
*Actual progress report...
As of earlier today we now have all proper dash warning lights working finally and a working fuel pump which is a HUGE plus, and a few other things that didn't work at all when I started are working properly now, so we now have working Fuel which the previous owner didn't but still no spark...
At my insistence, althout they were about triple the price I was expecting for each one, the genuine Lexus Electrical Wiring Manuals for the 93 and 97 (pre/non-immobilizer year OBD-II, I THINK?) SC400 have been ordered and are in-route to my buddy's place, scheduled to hopefully arrive one day this week.
In the meantime I've been staring at random incomplete diagrams found online for both years as my only reference source so progress is very slow.
*Interesting OBD-II tidbit...
To my suprise, with a bit more staring at tiny black and white 1996 SC400 wiring schematic sheet I tried to splice that Camry OBD-II diagnostic Data Link Connector into this SC400's new OBD-II engine harness earlier today with "gator clip" jumper wires and some careful temporary open heart surgery to the OBD-II harness near the ECU plugs.
I guess I did it right because my reader powered on and linked up the moment I plugged it into the connector and at first scan we got the all-clear but then I had my buddy turn the key to crank the engine for a few seconds and when he stopped I ran another scan. At that point the reader said the ECU was reporting the P1300 and P1305 codes (iirc) which the manual for the reader says is "Igniter 1 Circuit Malfunction" and "Igniter 2 Circuit Malfunction" for Toyota/Lexus vehicles.
Just for the fun of it I tried to clear the codes, ran another scan, and got the all-clear so that worked too. Then to be sure it was working right we turned the key to crank the engine again and then ran another scan and the P1300 and P1305 codes returned which was great to see and turned out to be VERY helpful!
Based on the OBD-II error codes the ECU reported, after a bit more staring at partial online SC400 wiring diagrams I located and began probing the igniter and coil connectors and found that there is no B+ signal getting to either Igniter or either Coil which explains the ECU's reported "Igniter Circuit Malfunction" codes for sure and points me in a helpful direction to search out and correct the total lack of ignition system power that the OBD-II system revealed and verified for me. I'm assuming it's either something in the engine bay we haven't noticed that didn't get plugged in or a blown fusible link although so far they all meter out with power on both sides or a relay that's not energizing or is possibly missing, or even possibly a connector pin-out discrepancy between the two different ECU systems and model years.
So now I'm trying to determine path and all connectors involved in that power path for an OBD-I car from the fusebox to the OBD-II engine harness to the igniters and coils, hoping that it's not an Immobilizer year OBD-II ECU.
Oh, and I TOTALLY forgot to mention that this car also used to have some sort of fancy aftermarket stereo system and expensive aftermarket alarm installed but the person who sold the car with no engine or transmission to the guy we got it from had also removed his fancy stereo and expensive alarm system and the car hasn't run since. So there's no telling if there's a cut wire or missing relay or added ignition-kill wiring somewhere in a kick-panel that could also be killing the ignition system either.
*Frivilous commentary and other thoughts about the ECU...
I'm slightly concerned about the possibility of the Lexus Immobilizer system because I have absolutely no way of resolving that in this car that doesn't even know what OBD-II is, much less the Immobilizer system, but if I can get the right diagrams with the full connector path info and it really is pre-Immobilizer then I'll be suprised if I don't have this car running within the next few weeks, if not sooner...
More to come as I stare at more wiring diagrams and hunt for the missing ignition system B+ signal and report on my next encounter with this car...
Last edited by zukikat; 04-11-11 at 02:13 AM.
04-11-11, 06:42 PM
#2
dude, did you see my reply in your other thread?
i appreciate your optimism, but i think you have no idea what you're getting into here.
you're going to power the ignition coils and igniters, then it won't fire because of the ECU immobilizer.
yank all that crap out, get a 92-94 harness, 92-94 ECU, reinstall, and be done.
i appreciate your optimism, but i think you have no idea what you're getting into here.
you're going to power the ignition coils and igniters, then it won't fire because of the ECU immobilizer.
yank all that crap out, get a 92-94 harness, 92-94 ECU, reinstall, and be done.
Last edited by cartmill; 04-11-11 at 06:48 PM.
04-11-11, 09:01 PM
#3
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wow... sounds like a total nightmare dude, might be best to walk away from this project. I did this obd1 to obd2 swap (95 to 98vvti): https://www.clublexus.com/forums/sc-...storation.html
I only took on this project because it was mostly bolt-on. i had a crashed 98 and swapped over parts and ran into issues when parts were missing- had to source very rare 98-2000 parts to complete this project but, was able to get it done without any issues to date. i make this suggestion of walking away from this because if you do not have all the parts needed (immobilizer key, ecu's, right harnesses,etc) it will be an extremely aggravating process. also, to add more difficulty to the mix, you cannot speak for the condition of the harnesses that was installed. I hate to sound negative about what i think you have here, but if i didnt have the whole car/parts to dissect,inspect and swap out myself..it would not have happened. let me know if there is anything i can guide you on in this process if you choose to continue and i will help...maybe you can gain some insight from the posting of my install
I only took on this project because it was mostly bolt-on. i had a crashed 98 and swapped over parts and ran into issues when parts were missing- had to source very rare 98-2000 parts to complete this project but, was able to get it done without any issues to date. i make this suggestion of walking away from this because if you do not have all the parts needed (immobilizer key, ecu's, right harnesses,etc) it will be an extremely aggravating process. also, to add more difficulty to the mix, you cannot speak for the condition of the harnesses that was installed. I hate to sound negative about what i think you have here, but if i didnt have the whole car/parts to dissect,inspect and swap out myself..it would not have happened. let me know if there is anything i can guide you on in this process if you choose to continue and i will help...maybe you can gain some insight from the posting of my install
04-11-11, 09:47 PM
#4
Thanks so far for all the feedback, and to cartmill for the production dates for the ECU and harness and engine I'm working with, that's a HUGE help believe it or not!
nextlevelcoupe, I appreciate the offer of guidance and I just might take you up on that if I feel like I'm making good progress but still can't get it done at some point over the next couple of weeks...
Note that this is not something I would've chosen to do if it hadn't been dumped in my lap as-is, but I'm definitely not giving up yet and I'm not actually discouraged at all yet either.
It's too early in the project for me to feel overwhelmed or consider surrendering yet and so far every step I've taken has gotten us very positive results in a very short amount of time.
Now that I've retro-fitted an OBD-II data link connector and it actually works so I can ask the ECU what it thinks in each step of the way, I'll simply be going step by step, letting the ECU tell me what isn't working next, and then follow the wiring diagrams between the two years and check each related junction point to see what's either unplugged or connected improperly or wired in a different pinout order until either the ECU tells me everything's fine and leaves me nowhere obvious to look next but still won't cough or sputter or start, or it actually tells me it's immobilized if there is such a code, or it starts, whichever comes first.
If it had been my car with no motor or tranny or harness in it I would've either tracked down the exact same year of everything or at least still an OBD-I year of power/drivetrain, harness, and ECU to match the car, or as I've told my buddy, if it was my car and this motor had to come back out, I would seriously consider an Aristo swap instead, being the Supra fan that I am... although I do like the 1UZ in my LS a lot!
We've got a 93 wiring book ordered and it has already shipped and I forget if he ordered a 96 or 97 wiring book that should also be on its' way. We'll see when it gets here. Plus if the 96 or 97 book's section on the security system and remote entry and such doesn't have any immobilizer references and wiring info or a separate section just for the immobilizer system then it means I'm in the clear for that obstacle as I'm about 60% certain I am at this point and this should actually work as I'm expecting after all...
The 96 service manual pdf I found online is incomplete and all out of order and of course the SC400 ECU section of the wiring portion of the file is missing and I can't find a downloadable pdf of the 93 books at all so far so I'm sitting in a holding pattern at this point until the two hard copies arrive hopefully one day this week.
Once I have the wiring books for both years I can compare junction blocks and fuse locations and all those things that I can't otherwise trace at this point...
nextlevelcoupe, I appreciate the offer of guidance and I just might take you up on that if I feel like I'm making good progress but still can't get it done at some point over the next couple of weeks...
Note that this is not something I would've chosen to do if it hadn't been dumped in my lap as-is, but I'm definitely not giving up yet and I'm not actually discouraged at all yet either.
It's too early in the project for me to feel overwhelmed or consider surrendering yet and so far every step I've taken has gotten us very positive results in a very short amount of time.
Now that I've retro-fitted an OBD-II data link connector and it actually works so I can ask the ECU what it thinks in each step of the way, I'll simply be going step by step, letting the ECU tell me what isn't working next, and then follow the wiring diagrams between the two years and check each related junction point to see what's either unplugged or connected improperly or wired in a different pinout order until either the ECU tells me everything's fine and leaves me nowhere obvious to look next but still won't cough or sputter or start, or it actually tells me it's immobilized if there is such a code, or it starts, whichever comes first.
If it had been my car with no motor or tranny or harness in it I would've either tracked down the exact same year of everything or at least still an OBD-I year of power/drivetrain, harness, and ECU to match the car, or as I've told my buddy, if it was my car and this motor had to come back out, I would seriously consider an Aristo swap instead, being the Supra fan that I am...
although I do like the 1UZ in my LS a lot! We've got a 93 wiring book ordered and it has already shipped and I forget if he ordered a 96 or 97 wiring book that should also be on its' way. We'll see when it gets here. Plus if the 96 or 97 book's section on the security system and remote entry and such doesn't have any immobilizer references and wiring info or a separate section just for the immobilizer system then it means I'm in the clear for that obstacle as I'm about 60% certain I am at this point and this should actually work as I'm expecting after all...
The 96 service manual pdf I found online is incomplete and all out of order and of course the SC400 ECU section of the wiring portion of the file is missing and I can't find a downloadable pdf of the 93 books at all so far so I'm sitting in a holding pattern at this point until the two hard copies arrive hopefully one day this week.
Once I have the wiring books for both years I can compare junction blocks and fuse locations and all those things that I can't otherwise trace at this point...
Last edited by zukikat; 04-11-11 at 09:53 PM.
04-13-11, 09:01 PM
#6
Latest Update
4-13-2011
Well the 93 and 96 SC300/SC400 factory Lexus wiring books arrived this evening and after just a quick glance at the 96 book so far I'm even more optomistic as there's no mention of anything beyond a starter kill and power main relay disable signal for the stock security system, and the starter works fine with a turn of the key, and I'm 99% certain the power main relay is already energizing in the 93 body when the key is turned to the ON position if it's the one I believe I've already tested last week so as I had hoped and suspected it really appears that the transponder based immobilizer system is not a factor in this project car.
I'm still inclined to think that either the rapid unconcerned removal of the aftermarket alarm system the car had 2 owners ago when the engine was originally removed or a blown or missing fuse or relay or cut wire that was tapped for that alarm system, or possibly an unplugged engine bay connector that I haven't looked for yet is at the heart of the "no power to the ignition system" problem that we have so far at this point.
I'm leaning that way in my thinking because the parking lights also don't work at all but the tail lights that they share a fuse with work just fine and so do the turn/hazards and lo and hi beam headlights, and parking lights are also sometimes tapped to be triggered as the visual indicators for an aftermarket alarm iirc...
I haven't really gone through the harnesses in the engine bay with a fine toothed comb or actually jacked the car up for a look from beneath it yet but now that I have the factory wiring books to tell me where each junction point connector is in the car for the ignition system's power path and I know that it doesn't pass through any additional security relays or modules than the ones I'm already aware of then something obvious should jump out at me within the next few days as I get another chance to go probing with my meter...
4-13-2011
Well the 93 and 96 SC300/SC400 factory Lexus wiring books arrived this evening and after just a quick glance at the 96 book so far I'm even more optomistic as there's no mention of anything beyond a starter kill and power main relay disable signal for the stock security system, and the starter works fine with a turn of the key, and I'm 99% certain the power main relay is already energizing in the 93 body when the key is turned to the ON position if it's the one I believe I've already tested last week so as I had hoped and suspected it really appears that the transponder based immobilizer system is not a factor in this project car.
I'm still inclined to think that either the rapid unconcerned removal of the aftermarket alarm system the car had 2 owners ago when the engine was originally removed or a blown or missing fuse or relay or cut wire that was tapped for that alarm system, or possibly an unplugged engine bay connector that I haven't looked for yet is at the heart of the "no power to the ignition system" problem that we have so far at this point.
I'm leaning that way in my thinking because the parking lights also don't work at all but the tail lights that they share a fuse with work just fine and so do the turn/hazards and lo and hi beam headlights, and parking lights are also sometimes tapped to be triggered as the visual indicators for an aftermarket alarm iirc...
I haven't really gone through the harnesses in the engine bay with a fine toothed comb or actually jacked the car up for a look from beneath it yet but now that I have the factory wiring books to tell me where each junction point connector is in the car for the ignition system's power path and I know that it doesn't pass through any additional security relays or modules than the ones I'm already aware of then something obvious should jump out at me within the next few days as I get another chance to go probing with my meter...
Last edited by zukikat; 04-13-11 at 09:06 PM.
Trending Topics
04-15-11, 03:51 AM
#9
Today's update is in the next post!
Pardon the long-winded ramblings and thoughts and commentary along the way in this reply and the following Update post...
I figure share as much as possible and welcome any comments and/or feedback for a better informed project...
Plus hopefully some of my semi-related ramblings will prove useful in other ways for other people too.
The immobilizer info, if either specific year of parts in this car that I'm dealing with actually had that full Lexus Immobilizer system, would almost definitely be revealed in the wiring book in some way, shape, or form, even if it's a suppliment.
So far I've only found the standard factory Toyota TDS "Theft Deterrant System" section with its' regular method of disabling these two years of the vehicle which would've been obsoleted and replaced by the transponder system and it's essentially the same old Toyota TDS security system I'm already used to seeing from mid 80's through mid 90's Toyotas and I'm totally familiar with how it works, unless they hid something from us on purpose which is always possible but I doubt it...
I see no signs of the late 90's Lexus Transponder "Immobilizer" system for the 93 model year, no suprise there, or the 96 model year either which I'm actually happy about for this project.
That's not to say that the older cars are simple to steal because they're not, but they don't require chipped keys like the last years do. It appears that transponder keys for these cars were introduced for the 1998 model year and although I'm dealing with an OBD-II ECU and such it appears that the ECU, harness, etc I'm working with is from a 96 SC, just old enough not to be totally immobilized... The replaceable security "chip" that the older models like these have in their security system is for the remotes, not the key itself.
The FSM for both cars would probably contain some full ECU pinouts and such listed all on one sheet instead of having to flip between sections of the wiring book to get "the whole picture" for any given connector and maybe having it might answer other connector questions more quickly but the factory wiring books are proving to be the key piece of this puzzle that I really needed...
It's funny you should ask because today I got my first hands-on time in the car with the two manuals so I'm no longer flying totally blind with this project and it looks like lots of accessory and sensor type stuff between the two years doesn't plug in, or so I've discovered...
Just from inadvertent observations while staring at the wiring book I noticed right off the bat that the alternator connector which is pictured within the schematic on the "starting" diagram page has the same number of wires but is a completely different shape as pictured on that same page in each of the two books and the starter solenoid connector shown on that same page in each book is also a different shape and that's without even checking what other plugs got "revised" in the newer model year. Which means the 92 harness won't plug into some parts of the 96 engine or accessories that I'm working with on the 96 engine. That's not to say that I couldn't hack some wiring and make those things function as-is but I'd rather try and make what I have work without any major harness hacking first if I can...
I also suspect that various sensors might have different operating ranges and different shaped plugs and such between the two model years so it's definitely not as simple as grabbing an OBD-I harness and connecting it to the OBD-II engine without having to scavenge other stuff and replacing some accessories and such at a minimum from the looks of it...
I'm actually astonished at how the OBD-II engine harness from the 96 SC400simply plugged directly into every appropriate body harness connection point in this 93 SC even though they're not all wired correctly for it, I'm not kidding. There were no changed plug shapes or new guide keys at all which is downright scary!!!
The problem with that is they changed the pinouts around in the connectors from year to year which means that you could unintentionally be putting power or ground where it shouldn't be or not putting it where it should (my current igniter/coil/injector problem), or even worse... like putting data and control pins to power or ground, which is a BAD thing... Not to mention the potential for overloading a gauge of wire or turning it unintentionally into a slow-blow fusible link and causing an electrical fire... THAT would SUCK!
Even the 93 ECU that doesn't have a snowball's chance in hell of running the 96 engine via the 96 harness (8-channel injection versus 4-channel injection, among other differences) also just plugs right in to the 96 ECU connectors, damit! I'm kinda pissed that Toyota got so lazy about it. I've NEVER seen them do that before, but then again I'm more used to the 1st - 3rd gen Supras that even within the same chassis got re-shaped plugs with the same pin sequences and exact same layouts that won't plug into each other whatsoever which they did almost every other model year for the same connectors in the same places on the car, usually with changes to the wire gauges as the loads increased with new features though...
As I slowly verify the pin-outs of the various unmatched (93/96) engine to body connectors in the car I'm also verifying the wire gauge of each pin at each side of each connections just to try and keep it safe.
Pardon the long-winded ramblings and thoughts and commentary along the way in this reply and the following Update post...
I figure share as much as possible and welcome any comments and/or feedback for a better informed project...
Plus hopefully some of my semi-related ramblings will prove useful in other ways for other people too.
So far I've only found the standard factory Toyota TDS "Theft Deterrant System" section with its' regular method of disabling these two years of the vehicle which would've been obsoleted and replaced by the transponder system and it's essentially the same old Toyota TDS security system I'm already used to seeing from mid 80's through mid 90's Toyotas and I'm totally familiar with how it works, unless they hid something from us on purpose which is always possible but I doubt it...
I see no signs of the late 90's Lexus Transponder "Immobilizer" system for the 93 model year, no suprise there, or the 96 model year either which I'm actually happy about for this project.
That's not to say that the older cars are simple to steal because they're not, but they don't require chipped keys like the last years do. It appears that transponder keys for these cars were introduced for the 1998 model year and although I'm dealing with an OBD-II ECU and such it appears that the ECU, harness, etc I'm working with is from a 96 SC, just old enough not to be totally immobilized... The replaceable security "chip" that the older models like these have in their security system is for the remotes, not the key itself.
The FSM for both cars would probably contain some full ECU pinouts and such listed all on one sheet instead of having to flip between sections of the wiring book to get "the whole picture" for any given connector and maybe having it might answer other connector questions more quickly but the factory wiring books are proving to be the key piece of this puzzle that I really needed...
Just from inadvertent observations while staring at the wiring book I noticed right off the bat that the alternator connector which is pictured within the schematic on the "starting" diagram page has the same number of wires but is a completely different shape as pictured on that same page in each of the two books and the starter solenoid connector shown on that same page in each book is also a different shape and that's without even checking what other plugs got "revised" in the newer model year. Which means the 92 harness won't plug into some parts of the 96 engine or accessories that I'm working with on the 96 engine. That's not to say that I couldn't hack some wiring and make those things function as-is but I'd rather try and make what I have work without any major harness hacking first if I can...
I also suspect that various sensors might have different operating ranges and different shaped plugs and such between the two model years so it's definitely not as simple as grabbing an OBD-I harness and connecting it to the OBD-II engine without having to scavenge other stuff and replacing some accessories and such at a minimum from the looks of it...
I'm actually astonished at how the OBD-II engine harness from the 96 SC400simply plugged directly into every appropriate body harness connection point in this 93 SC even though they're not all wired correctly for it, I'm not kidding. There were no changed plug shapes or new guide keys at all which is downright scary!!!
The problem with that is they changed the pinouts around in the connectors from year to year which means that you could unintentionally be putting power or ground where it shouldn't be or not putting it where it should (my current igniter/coil/injector problem), or even worse... like putting data and control pins to power or ground, which is a BAD thing... Not to mention the potential for overloading a gauge of wire or turning it unintentionally into a slow-blow fusible link and causing an electrical fire... THAT would SUCK!
Even the 93 ECU that doesn't have a snowball's chance in hell of running the 96 engine via the 96 harness (8-channel injection versus 4-channel injection, among other differences) also just plugs right in to the 96 ECU connectors, damit! I'm kinda pissed that Toyota got so lazy about it. I've NEVER seen them do that before, but then again I'm more used to the 1st - 3rd gen Supras that even within the same chassis got re-shaped plugs with the same pin sequences and exact same layouts that won't plug into each other whatsoever which they did almost every other model year for the same connectors in the same places on the car, usually with changes to the wire gauges as the loads increased with new features though...
As I slowly verify the pin-outs of the various unmatched (93/96) engine to body connectors in the car I'm also verifying the wire gauge of each pin at each side of each connections just to try and keep it safe.
Last edited by zukikat; 04-15-11 at 03:59 AM.
04-15-11, 03:52 AM
#10
Today's Update with the new wiring books...
4-14-2011
So before the books arrived, as posted earlier I managed to successfully splice an OBD-II data check connector socket into this 93 SC to use my OBD-II reader on this car and I was getting a P1300 and P1305 (iirc) Igniter 1 & 2 Circuit Malfucions... My meter verified that the power pin in both connectors for the two igniters had no B+, as the two coils didn't either and it's a safe assumption at that point that neither do the injectors. At least not yet anyway...
Turns out that the "Ignition Main Relay" (iirc) that appears to be SC400 specific and only found in the OBD-I years (it's a 1UZ thing, not a 2JZ thing apparently) has been totally eliminated by the time the 96 model was introduced and the related power circuits were redesigned as a result. So the power output circuit formerly routed through that relay from the Engine Bay Fusebox got utilized in a totally different way within the 96 engine harness to redistribute the updated power load for some newly added circuits instead.
Problem is, the 93 model SC doesn't know about any of that...
Plus for the updated 96 model with the 8-channel injector system instead of the 4-channel version the 93 has, the ignition components were given their very own totally separate additional power wires from the rest of the EFI system, not just one but two wires for better load balancing within the harness, that go to an entirely different point in the engine harness (and into the passenger kick panel) for the 96 model year.
The revised power circuit junction points and added wires inside the engine harness for the 96 model's ignition circuits run all the way through the engine harness and got relocated into a connector in the passenger kick panel of the 96 which plugs into two unused and non-existent pins in the 93 version of that matching connector in the 93's passenger kick panel. Hence the malfunction of the two igniter circuits due to no B+...
So my original Ignition Main Relay B+ power feed from the 93's fusebox that's supposed to be running the ignition circuit is apparently now powering oxygen sensor heaters and other ECU related things instead of giving me a functional ignition system... Not an impossible fix at all, but certainly an annoying one.
Suprisingly, every other pin in that connector matches up perfectly to run the fuel pump and some sensors and a few other things.
So it's literally a matter of figuring out how to properly/safely feed the necessary B+ signal to those two wires in the engine harness, or tap it in some other way, to get the ignition system up and running...
I see no security related relays or control signal leads in the 96 wiring book for that circuit and apparently these pins were actually used in most model years for the SC's whenever a 2JZ-GE was installed in the car so I guess they decided to stop using the original 1UZ exclusive pinouts and standardize the chassis at some point instead of having specific/different 1UZ and 2JZ body harness configurations.
Initial thoughts for solutions to the B+ lack of spark problem so far...
For a quick and easy band-aid type solution I could probably run a wire from the positive battery terminal and splice it into the B+ pin of one of the igniters and there's a really good chance that it would back-feed from there into the other igniter and the coils and the injectors, assuming there aren't any rectifiers (diodes) hidden along those paths in the loom, or at least half of them would be powered anyway at a minimum and there's a really good chance that the car would actually start as-is at that point but I suspect that the igniter's fairly thin B+ wire's gauge isn't beefy enough to run all those components for very long without acting like an overloaded fusible link, plus without a fuse in that hypothetical jumper wire from the battery it wouldn't be safe or reliable either...
I "might" try feeding B+ from the ignition main relay to the B+ pin of BOTH igniters and seehow that works but I haven't totally decided yet.
I'm also contemplating just bridging the two 96 igniter/coil/injector B+ wires in the passenger kick panel into the existing EFI (ECU/FP) B+ power wire that's actually directly between the two 96 B+ wires in question in the engine harness side of that exact same connector but I haven't finished chasing down the full EFI circuit in both years to compare the loads yet to make sure I'm not overloading anything...
I'll probably put something temporary but safe in place for those new 96 B+ wires just to make sure the car will actually fire up and run and if so then I'll create a proper permanent solution that I'm satisfied with the safety and reliability of, but no matter what I do I'll definitely post it up as I go along...
Or if I wanted to physically re-route the 96 engine harness back almost exactly to the 93 layout as far as this little Ignition B+ problems goes I could cut open the wiring loom of the 96 engine harness where the igniter wiring branch and fusebox power branch both happen to fork out of it, cut the added 96 EFI main B+ wire off the Ignition Main Relay output wire of the 3-pin fusebox connector where it currently lines up in the mismatched years' mated connections, splice the engine harness end of it into the neighboring original EFI main B+ wire that's next to it on the 3-pin fusebox connector to put that portion back like it would be in a 93 engine harness, then splice the cut wire from the fusebox side of the Ignition Main Relay B+ feed into the two new 96 Igniter/Coil/Injector B+ wires inside the engine harness loom, and then solder everything neatly and tape it all back up and then theoretically the whole B+ problem would almost definitely be solved with similar overall power loads and fuse sizes between the two model years and I'd be done, and I still might end up going that route but I'm really hoping to find an even easier solution without having to hack up the harness if I can find another clean and safe way to do it instead. We'll see...
Before I even consider going hacking into the 96 engine harness for a permanent solution, I want to hear the engine start or at least see it throw ignition spark and make sure there aren't any other unexpected trouble codes first. So a very momentary band-aid will probably be the next step after I'm satisfied that all the other 96 engine harness to 93 body connector pin-outs are correct...
Part of my hesitation to hack the 96 engine harness is if he gets impatient and decides to give up and pull the motor and sell it and get all 93 stuff before I get it running as-is, I'd rather the 96 engine harness not be hacked into at all or not to have to undo that work to put it back to right for a 96.
The more I think about that the better I like the sound of it but I've been up since yesterday and the sun's coming up so I'll have to think about it more when I'm not falling asleep at the keyboard...
*Side note, body interior connectors involved in this project so far:
There are 4 primary engine harness to body connectors besides the ECU and ABS and TRAC and a couple of a/c and hydro-fan ecu related connectors and such, and the connector with the ignition B+ pins in it that I'm referring to above is one of those four. It's labelled IJ1 in both years. I presume IJ2 and IK1 and IK2 are the other three but I'm falling asleep so I forget at the moment...
But I sat and verified pin by pin on the 96 engine harness side and on the 93 body connector side of that connector today with my findings mentionned above already...
Now I plan to take the time to verify the pinouts on both sides of the other three connectors that the 96 harness connects to in the 93 chassis' passenger kick panel which should take me an afternoon or evening one day this weekend.
Once I've verified exactly what's what with those plugs, if they line up pretty much pin for pin as well as this one did with either no differences or only minor ones like this ignition components power issue then I'll be very suprised if the car doesn't start when I apply power to the ignition system hopefully this weekend, weather and work allowing...
Now that doesn't mean it'll run great and be totally drivable at that point as none of the hydro-fan lines are connected and there are no hose clamps on the radiator hoses yet, and thus no coolant in the engine yet, and I suspect that the tranny cooler pipes don't have their coupler hoses on 'em yet, and so on and so on, but my main goal for this weekend is to get spark and then undo the hack-job that was done to the fuel pump ecu and verify that the main Engine/ECT ECU actually has control of the pump like it should.
THEN we'll plumb all the lines and add the remaining fluids it lacks and find out what other suprises we might be in for...
But then again once I have the igniters/coils/injectors properly powered and I turn the key to try and start the car the ECU might decide something else isn't to its satisfaction and pile on additional trouble codes...
If that happens I'll have to proceed as it suggests.
Again, so far I'm not seeing anything that's making me think this project won't be running fairly soon as-is but of course time will tell...
Another seemingly minor obstacle is that at some point I'll have to figure out how to disable/eliminate the 96 trac circuits and make sure the tranny will function properly in this car because this car didn't have trac but the 96 did. I believe the trac ecu interacts with the tranny and the ABS but I haven't stared at the diagrams or done any research to find out how to tell a trac based main ECU that the car it's in never had trac.
Minor ABS info tidbit...
Apparently even the ABS module is different for a trac car than a non-trac version of the same car. The ABS module in a trac equipped SC has 3 wide white connectors instead of 2, the 2 "body connectors" in the non-trac version cars are smaller than the equivalent connectors on a car that has trac and the third connector is in the engine harness, and the actual trac ecu's two grey main connectors are both part of the engine harness.
I originally bought the TRAC ecu and matching ABS module out of the 92 SC400 junkyard car just to verify some "extra" engine harness connectors in the 93 body that I wasn't sure where they went and now all plugs in the 96 engine harness and 93 body are totally accounted for, although the trac version ABS ecu is useless in this car since it won't plug in at all and the supporting trac-pump, relays, fuses, etc for the trac system don't exist in this car either so I need to figure out if it's as easy as leaving the plugs undone or if I've got some patchwork to do to bypass it for the 96 main ECU...
*** Question...
After we got the Igniton system malfuction codes and had no idea about the history of the existing igniters my buddy decided to call the previous owner who was involved in dropping this engine in the car before we got it and he said that the igniters that are currently plugged into the 96 engine harness are the ones that were originally running the 93 car before the swap.
I've already verified that the connector pin-outs on both igniters is the same for both model years but does anyone know if the actual igniters themselves were ever revised at any point, like maybe for a hotter spark, or are they basically the same and totally interchangeable between OBD-I and OBD-II model years? I can get the P/N off the top one next chance I get to be with the car and post the number if that helps at all...
I will say that they plug right in, not that that means much...
4-14-2011
So before the books arrived, as posted earlier I managed to successfully splice an OBD-II data check connector socket into this 93 SC to use my OBD-II reader on this car and I was getting a P1300 and P1305 (iirc) Igniter 1 & 2 Circuit Malfucions... My meter verified that the power pin in both connectors for the two igniters had no B+, as the two coils didn't either and it's a safe assumption at that point that neither do the injectors. At least not yet anyway...
Turns out that the "Ignition Main Relay" (iirc) that appears to be SC400 specific and only found in the OBD-I years (it's a 1UZ thing, not a 2JZ thing apparently) has been totally eliminated by the time the 96 model was introduced and the related power circuits were redesigned as a result. So the power output circuit formerly routed through that relay from the Engine Bay Fusebox got utilized in a totally different way within the 96 engine harness to redistribute the updated power load for some newly added circuits instead.
Problem is, the 93 model SC doesn't know about any of that...
Plus for the updated 96 model with the 8-channel injector system instead of the 4-channel version the 93 has, the ignition components were given their very own totally separate additional power wires from the rest of the EFI system, not just one but two wires for better load balancing within the harness, that go to an entirely different point in the engine harness (and into the passenger kick panel) for the 96 model year.
The revised power circuit junction points and added wires inside the engine harness for the 96 model's ignition circuits run all the way through the engine harness and got relocated into a connector in the passenger kick panel of the 96 which plugs into two unused and non-existent pins in the 93 version of that matching connector in the 93's passenger kick panel. Hence the malfunction of the two igniter circuits due to no B+...
So my original Ignition Main Relay B+ power feed from the 93's fusebox that's supposed to be running the ignition circuit is apparently now powering oxygen sensor heaters and other ECU related things instead of giving me a functional ignition system... Not an impossible fix at all, but certainly an annoying one.
Suprisingly, every other pin in that connector matches up perfectly to run the fuel pump and some sensors and a few other things.
So it's literally a matter of figuring out how to properly/safely feed the necessary B+ signal to those two wires in the engine harness, or tap it in some other way, to get the ignition system up and running...
I see no security related relays or control signal leads in the 96 wiring book for that circuit and apparently these pins were actually used in most model years for the SC's whenever a 2JZ-GE was installed in the car so I guess they decided to stop using the original 1UZ exclusive pinouts and standardize the chassis at some point instead of having specific/different 1UZ and 2JZ body harness configurations.
Initial thoughts for solutions to the B+ lack of spark problem so far...
For a quick and easy band-aid type solution I could probably run a wire from the positive battery terminal and splice it into the B+ pin of one of the igniters and there's a really good chance that it would back-feed from there into the other igniter and the coils and the injectors, assuming there aren't any rectifiers (diodes) hidden along those paths in the loom, or at least half of them would be powered anyway at a minimum and there's a really good chance that the car would actually start as-is at that point but I suspect that the igniter's fairly thin B+ wire's gauge isn't beefy enough to run all those components for very long without acting like an overloaded fusible link, plus without a fuse in that hypothetical jumper wire from the battery it wouldn't be safe or reliable either...
I "might" try feeding B+ from the ignition main relay to the B+ pin of BOTH igniters and seehow that works but I haven't totally decided yet.
I'm also contemplating just bridging the two 96 igniter/coil/injector B+ wires in the passenger kick panel into the existing EFI (ECU/FP) B+ power wire that's actually directly between the two 96 B+ wires in question in the engine harness side of that exact same connector but I haven't finished chasing down the full EFI circuit in both years to compare the loads yet to make sure I'm not overloading anything...
I'll probably put something temporary but safe in place for those new 96 B+ wires just to make sure the car will actually fire up and run and if so then I'll create a proper permanent solution that I'm satisfied with the safety and reliability of, but no matter what I do I'll definitely post it up as I go along...
Or if I wanted to physically re-route the 96 engine harness back almost exactly to the 93 layout as far as this little Ignition B+ problems goes I could cut open the wiring loom of the 96 engine harness where the igniter wiring branch and fusebox power branch both happen to fork out of it, cut the added 96 EFI main B+ wire off the Ignition Main Relay output wire of the 3-pin fusebox connector where it currently lines up in the mismatched years' mated connections, splice the engine harness end of it into the neighboring original EFI main B+ wire that's next to it on the 3-pin fusebox connector to put that portion back like it would be in a 93 engine harness, then splice the cut wire from the fusebox side of the Ignition Main Relay B+ feed into the two new 96 Igniter/Coil/Injector B+ wires inside the engine harness loom, and then solder everything neatly and tape it all back up and then theoretically the whole B+ problem would almost definitely be solved with similar overall power loads and fuse sizes between the two model years and I'd be done, and I still might end up going that route but I'm really hoping to find an even easier solution without having to hack up the harness if I can find another clean and safe way to do it instead. We'll see...
Before I even consider going hacking into the 96 engine harness for a permanent solution, I want to hear the engine start or at least see it throw ignition spark and make sure there aren't any other unexpected trouble codes first. So a very momentary band-aid will probably be the next step after I'm satisfied that all the other 96 engine harness to 93 body connector pin-outs are correct...
Part of my hesitation to hack the 96 engine harness is if he gets impatient and decides to give up and pull the motor and sell it and get all 93 stuff before I get it running as-is, I'd rather the 96 engine harness not be hacked into at all or not to have to undo that work to put it back to right for a 96.
The more I think about that the better I like the sound of it but I've been up since yesterday and the sun's coming up so I'll have to think about it more when I'm not falling asleep at the keyboard...
*Side note, body interior connectors involved in this project so far:
There are 4 primary engine harness to body connectors besides the ECU and ABS and TRAC and a couple of a/c and hydro-fan ecu related connectors and such, and the connector with the ignition B+ pins in it that I'm referring to above is one of those four. It's labelled IJ1 in both years. I presume IJ2 and IK1 and IK2 are the other three but I'm falling asleep so I forget at the moment...
But I sat and verified pin by pin on the 96 engine harness side and on the 93 body connector side of that connector today with my findings mentionned above already...
Now I plan to take the time to verify the pinouts on both sides of the other three connectors that the 96 harness connects to in the 93 chassis' passenger kick panel which should take me an afternoon or evening one day this weekend.
Once I've verified exactly what's what with those plugs, if they line up pretty much pin for pin as well as this one did with either no differences or only minor ones like this ignition components power issue then I'll be very suprised if the car doesn't start when I apply power to the ignition system hopefully this weekend, weather and work allowing...
Now that doesn't mean it'll run great and be totally drivable at that point as none of the hydro-fan lines are connected and there are no hose clamps on the radiator hoses yet, and thus no coolant in the engine yet, and I suspect that the tranny cooler pipes don't have their coupler hoses on 'em yet, and so on and so on, but my main goal for this weekend is to get spark and then undo the hack-job that was done to the fuel pump ecu and verify that the main Engine/ECT ECU actually has control of the pump like it should.
THEN we'll plumb all the lines and add the remaining fluids it lacks and find out what other suprises we might be in for...
But then again once I have the igniters/coils/injectors properly powered and I turn the key to try and start the car the ECU might decide something else isn't to its satisfaction and pile on additional trouble codes...
If that happens I'll have to proceed as it suggests.
Again, so far I'm not seeing anything that's making me think this project won't be running fairly soon as-is but of course time will tell...
Another seemingly minor obstacle is that at some point I'll have to figure out how to disable/eliminate the 96 trac circuits and make sure the tranny will function properly in this car because this car didn't have trac but the 96 did. I believe the trac ecu interacts with the tranny and the ABS but I haven't stared at the diagrams or done any research to find out how to tell a trac based main ECU that the car it's in never had trac.
Minor ABS info tidbit...
Apparently even the ABS module is different for a trac car than a non-trac version of the same car. The ABS module in a trac equipped SC has 3 wide white connectors instead of 2, the 2 "body connectors" in the non-trac version cars are smaller than the equivalent connectors on a car that has trac and the third connector is in the engine harness, and the actual trac ecu's two grey main connectors are both part of the engine harness.
I originally bought the TRAC ecu and matching ABS module out of the 92 SC400 junkyard car just to verify some "extra" engine harness connectors in the 93 body that I wasn't sure where they went and now all plugs in the 96 engine harness and 93 body are totally accounted for, although the trac version ABS ecu is useless in this car since it won't plug in at all and the supporting trac-pump, relays, fuses, etc for the trac system don't exist in this car either so I need to figure out if it's as easy as leaving the plugs undone or if I've got some patchwork to do to bypass it for the 96 main ECU...
*** Question...
After we got the Igniton system malfuction codes and had no idea about the history of the existing igniters my buddy decided to call the previous owner who was involved in dropping this engine in the car before we got it and he said that the igniters that are currently plugged into the 96 engine harness are the ones that were originally running the 93 car before the swap.
I've already verified that the connector pin-outs on both igniters is the same for both model years but does anyone know if the actual igniters themselves were ever revised at any point, like maybe for a hotter spark, or are they basically the same and totally interchangeable between OBD-I and OBD-II model years? I can get the P/N off the top one next chance I get to be with the car and post the number if that helps at all...
I will say that they plug right in, not that that means much...
Last edited by zukikat; 04-15-11 at 06:10 AM.
04-15-11, 06:06 AM
#11
So far for this project I've probably spent a couple of afternoons in the junkyard where I also scored two very hard to get and damn near PERFECT factory power mirrors for my "OBS" K1500 200k+ mile TBI 5.7L 4x4 Suburban (YAY!) and a handful of minor nick-nacks for my LS400 and a full 96 DX Camry Spindle/Hub/CV-Shaft assembly for this same buddy's current commuter car (next project, I HATE Front Wheel Drive) while we were at the junkyard, and spent an evening or two casually helping him tinker with unplugged and broken marker lights and erratic turn signal issues (a worn out/loose bulb socket and two crappy p.o.s. aftermarket BLUE light bulbs in the TURN signals, WTH???) and figuring out where all the totally disassembled interior seats and panels belong and where their connectors plug into and exploring the realm of disconnected and missing oil/coolant/steering/tranny/hydro-fan hoses and stuff like that, and maybe 24 hours total at most so far staring at crappy online wiring diagrams and the factory wiring books since he got the car, and maybe 8 hours total actually verifying connections and trying to make it run to this point.
As a result of my efforts to date I've got all loose/unplugged/unknown/"spare" engine harness plugs accounted for and now mated to the body afaik with the exception of a black oval 2-pin engine harness plug (female, iirc) near the engine bay fusebox that looks like a VSV connector to me but doesn't seem to have any mate and a tiny black long thin rectangular 2-pin plug by the passenger headlight that I don't recognize and think it might be a coolant level sensor plug but I don't see a place on the reservoir for it, and I've gotten the "fuel pump not working" mystery solved and the fuel pump operational on day 1 without even having any wiring diagrams yet at that point, discovered the "12-Volt mod" on the Fuel Pump ECU connector today which isn't correct and will be undone this weekend, got the potential transponder immobilizer system obstacle determined 99% confident as a non-issue in this car, got an OBD-II Diagnostic Data Link Connector successfully retro-fitted and proven fully operational with my OBD-II reader and got helpful troubleshooting codes as a result (temporary patch-in, will be done clean/permanent once the car runs), and located and isolated the "lack of spark" portion of the "no fuel and no spark" problem and formed a game-plan for resolving it after I verify the remaining unchecked harness to body connection pinouts to my satisfaction.
Not too bad of progress so far I guess...
It'd be nice to see some spark though for sure...
Basically about 2 weeks of my buddy having posession of the car but only maybe 2 full days total of actual troubleshooting work on my part if that much (including staring at manuals at home after hours) while taking my time and being slow and casual and somewhat methodical about it, and by this point I'm very confident that if it was absolutely necessary I could probably throw together some sort of basic simple quick and dirty temporary shade-tree ignition B+ wiring band-aid and turn the key and watch it fire up tomorrow if I really had to get it running on the spot.
Hopefully not overconfidence on my part... We'll see...
As a result of my efforts to date I've got all loose/unplugged/unknown/"spare" engine harness plugs accounted for and now mated to the body afaik with the exception of a black oval 2-pin engine harness plug (female, iirc) near the engine bay fusebox that looks like a VSV connector to me but doesn't seem to have any mate and a tiny black long thin rectangular 2-pin plug by the passenger headlight that I don't recognize and think it might be a coolant level sensor plug but I don't see a place on the reservoir for it, and I've gotten the "fuel pump not working" mystery solved and the fuel pump operational on day 1 without even having any wiring diagrams yet at that point, discovered the "12-Volt mod" on the Fuel Pump ECU connector today which isn't correct and will be undone this weekend, got the potential transponder immobilizer system obstacle determined 99% confident as a non-issue in this car, got an OBD-II Diagnostic Data Link Connector successfully retro-fitted and proven fully operational with my OBD-II reader and got helpful troubleshooting codes as a result (temporary patch-in, will be done clean/permanent once the car runs), and located and isolated the "lack of spark" portion of the "no fuel and no spark" problem and formed a game-plan for resolving it after I verify the remaining unchecked harness to body connection pinouts to my satisfaction.
Not too bad of progress so far I guess...
It'd be nice to see some spark though for sure...
Basically about 2 weeks of my buddy having posession of the car but only maybe 2 full days total of actual troubleshooting work on my part if that much (including staring at manuals at home after hours) while taking my time and being slow and casual and somewhat methodical about it, and by this point I'm very confident that if it was absolutely necessary I could probably throw together some sort of basic simple quick and dirty temporary shade-tree ignition B+ wiring band-aid and turn the key and watch it fire up tomorrow if I really had to get it running on the spot.
Hopefully not overconfidence on my part... We'll see...
04-17-11, 02:23 AM
#13
IT LIVES!!!
4-16-2011
So the immobilizer and/or security systems definitely are NOT an issue for this project.
I didn't have to touch anything related to the security system whatsoever.
This afternoon after about 20 minutes of re-checking a couple of circuits on the car with my meter I powered up the iginition system (B+ to the igniters/coils/injectors) with a temporary jump from the EFI Main circuit's B+ in the passenger kick-panel connector, disconnected both distributor coil wires and set one on the valve cover with a 1/2" gap between the wire's center conductor and the metal of the valve cover, turned the key to start for a few seconds and as the motor cranked slowly on the weak battery we saw lightning from the ignition system for the first time ever since this 96 OBD-II tranny/engine/engine harness/ecu were dropped into this 93 SC400 by the previous owner several years ago...
YAY!!!
So I reconnected both distributors' coil wires to their coils, re-scanned and then reset the ECU with my OBD-II reader again just for the heck of it even though there were no codes showing, then we turned the key to the start position, and actually got a few coughs and sputters and signs of life from this engine for the first time in this car before the already weak battery wouldn't run the starter anymore.
After re-checking for any new OBD-II trouble codes now that we have spark and not getting any complaints from the ECU at all, not even the former P1300 and P1305 that would've normally reappeared by now from turning the key to start, we added a battery jump box to the weak battery, turned the key to start again, and she coughed a bit more and then barked rather loudly a few times then reluctantly fired up briefly but stalled moments later, and then with a grin on my buddy's face and one more turn of the key she eagerly roared to life on 4+ year old gas with a tank so empty the low fuel light is on and the needle's on E!!!
She didn't really want to idle yet but it's no suprise that after sitting for so long she'll need a few minutes of being driven to really learn her parameters.
But the good news is that all 8 cylinders were hitting and a tap of the throttle to watch the tach respond a few seconds before turning the key off made the tach climb as expected so it's all good and we're both really happy.
It's not finished by any means, it hasn't moved from the driveway yet, there is no exhaust system on the car whatseoever yet (open headers!!!), it doesn't even have any fluids besides oil in it at all yet (not even coolant!), and the temporary source of B+ and thin gauge of jumper wire that I used to power the ignition system for this test will not be the final setup, so there's still a bit of mechanic work left to do before we can drive it that was all being put off 'till we knew it'd actually fire up and that work as-is and that work will be happening next...
Plus there's still the question of the 96 ECU and harness being from a TRAC car and this car not having TRAC which is the next wiring investigation task to check out.
***
But just to let everyone know... All that was necessary to make this 1996 SC400 OBD-II ECU and harness and engine run in this 93 OBD-I SC400 was to plug in all connectors (which DO all plug right in from the 96 engine harness to the 93 car!!!) then jump 2 wires in one kick-panel connector to a B+ (power) source from an adjacent pin, turn the key, and hear it run as-is!
After we first got spark before I reconnected the coil wires to the distributors I undid the previous owner's fuel pump computer "12-volt mod" wiring change to the 93 harness and put that wiring totally back to stock before we finally tried to actually start the car with a functional ignition system and the fuel pump DID work properly through the stock 93 wiring with the 96 main ECU controlling the 93's fuel pump computer through its' totally unmolested 96 engine harness as expected.
Generic disclaimer, of course...
This project SC400 now starts and runs with only a very minor change being necessary to essentially just 3 wires in the 96 engine harness but it has yet to be driven so there may be other suprises I don't know about yet and I'll continue to post anything else I encounter until it's fully running and driving and making my buddy's 40+ mile 1-way work commute with no problems...
But considering the fact that the engine, transmission, engine harness, and main ECU were bought as a matched set and the car actually starts with such a minor wiring change I'll be suprised if there are any engine or tranny management issues at all...
*Initial reflections on the work in progress...
So the answer to the pre-immobilizer OBD-I to OBD-II swap being possible is that with a matched engine and tranny and engine harness and main ECU from a 96 OBD-II SC400 there is one power source configuration change that has to be modified with 4 power wires involved to mate it to an OBD-I 93 SC400 and everything else so far just plugs right in and works. I suspect that the 97 version would work about the same although I haven't seen a wiring book for it to compare, and I have a feeling that with the genuine Lexus wiring books for the appropriate year I could probably find a way around the 98+ key transponder security/immobilizer system with an aftermarket gadget of some kind and probably make one of those ECU's and its' matched engine harness and engine also start and run in the older model years too without much alteration to the harnesses unless Toyota/Lexus really changed connector shapes/sizes and such or really screwed with the wiring more than expected.
*Somewhat summarized status update...
Now that it's been verified that this setup WILL actually run with very minimal wiring alterations being needed, to complete this project I intend to essentially leave the 93 wiring fully untouched and cut and splice at 2 points in the 96 engine harness as my permanent solution which will allow me to recombine the split-load dual-feed EFI circuit in the 96 engine harness back onto its' own single 30A fuse as it would be in a 93 and to recombine the split-load dual-feed Ignition system circuit and power it with the 30A IGN fuse from this 93 model which are the same sized fuses that were used in 96 anyway... Essentially it's making the 96 harness match up with the 93 body wiring and relays and circuit fuses while retaining the revised split-load wiring of the 96 main ECU system...
To be a bit more precise on my intentions with pin numbers and such...
To re-route the secondary EFI B+ wire (EB2 pin 2 in 96) into the main EFI B+ wire at the EB2 connector (EB2 pin 3 in both years, black with red stripe and really thick) and tie EB2 pin 2 back into the igniter/coils/injectors circuit B+ wire in the 96 harness where it normally goes in a 93 is my goal.
I'll most likely get into the wire loom a few inches into the 96 engine harness side of the EB2 connector near the engine bay fuse box, then cut the EB2 pin 2 wire within the engine harness and splice the engine side of it to the EB2 pin 3 wire to recombine both parts of the EFI circuit back together within the 96 engine harness nearest to the source, and then tie the fusebox side of that cut pin 2 wire in the engine harness into the car's ignition system circuit as it would've been in a 93 which puts the ignition circuit back onto the correct relay and fuse for a 93.
I'll probably just connect the fusebox side pin 2 wire into the ignition circuit within the engine harness by attaching it to the the B+ wires of both igniters near their connectors and tie their B+ wires together for improved load capability back into the 96 harness as my primary IGN B+ feed point, then I'll complete the 96 engine harness' split IGN circuit by tying its' two IGN B+ wires together at the other end of the harness where they both meet which is the IJ1 pins 3 and 7 in the passenger kick panel that don't exist (are unused pins) in that area of a 93 SC400 at all.
Note that IJ1 pin 7 runs BOTH igniters and just the coil closest to the fusebox while IJ1 pin 3 runs the other coil over by the thermostat PLUS it also runs the entire set of of fuel injectors so combining those two pins at the IJ1 kick-panel connector is the easiest means of delivering B+ from the 93 Ignition Main Relay circuit to the 96 harness' divided parts of the full ignition circuit. So I need to be sure to make a solid electrical connection when combining those two pins as this configuration decision means that a failure of that connection would remove power from ALL injectors and ONE coil without any other signs of why the car shut down in that case... I could cut into the 96 harness at some other point and make that same type of connection but this is easier and cleaner and should be totally reliable with a good soldering of those two wires.
*Additional known remaining troubleshooting notes so far...
I haven't chased down the inoperative parking lights issue or the cause of the AIR-BAG light being on at all times even with no key in the ignition, either of which may or may not be related to the 96 engine harness, but those are both fairly low on the to-do list considering the car still needs hoses and fluids and such just to become operable...
So that's the latest at this point.
More to come after I finish those wire changes and we begin adding fluids and see if she'll move on her own for the first time since she showed up in my buddy's driveway 2 weeks ago which will apparently be the first time she's been drivable at all in years...
4-16-2011
So the immobilizer and/or security systems definitely are NOT an issue for this project.
I didn't have to touch anything related to the security system whatsoever.
This afternoon after about 20 minutes of re-checking a couple of circuits on the car with my meter I powered up the iginition system (B+ to the igniters/coils/injectors) with a temporary jump from the EFI Main circuit's B+ in the passenger kick-panel connector, disconnected both distributor coil wires and set one on the valve cover with a 1/2" gap between the wire's center conductor and the metal of the valve cover, turned the key to start for a few seconds and as the motor cranked slowly on the weak battery we saw lightning from the ignition system for the first time ever since this 96 OBD-II tranny/engine/engine harness/ecu were dropped into this 93 SC400 by the previous owner several years ago...
YAY!!!
So I reconnected both distributors' coil wires to their coils, re-scanned and then reset the ECU with my OBD-II reader again just for the heck of it even though there were no codes showing, then we turned the key to the start position, and actually got a few coughs and sputters and signs of life from this engine for the first time in this car before the already weak battery wouldn't run the starter anymore.
After re-checking for any new OBD-II trouble codes now that we have spark and not getting any complaints from the ECU at all, not even the former P1300 and P1305 that would've normally reappeared by now from turning the key to start, we added a battery jump box to the weak battery, turned the key to start again, and she coughed a bit more and then barked rather loudly a few times then reluctantly fired up briefly but stalled moments later, and then with a grin on my buddy's face and one more turn of the key she eagerly roared to life on 4+ year old gas with a tank so empty the low fuel light is on and the needle's on E!!!
She didn't really want to idle yet but it's no suprise that after sitting for so long she'll need a few minutes of being driven to really learn her parameters.
But the good news is that all 8 cylinders were hitting and a tap of the throttle to watch the tach respond a few seconds before turning the key off made the tach climb as expected so it's all good and we're both really happy.
It's not finished by any means, it hasn't moved from the driveway yet, there is no exhaust system on the car whatseoever yet (open headers!!!), it doesn't even have any fluids besides oil in it at all yet (not even coolant!), and the temporary source of B+ and thin gauge of jumper wire that I used to power the ignition system for this test will not be the final setup, so there's still a bit of mechanic work left to do before we can drive it that was all being put off 'till we knew it'd actually fire up and that work as-is and that work will be happening next...
Plus there's still the question of the 96 ECU and harness being from a TRAC car and this car not having TRAC which is the next wiring investigation task to check out.
***
But just to let everyone know... All that was necessary to make this 1996 SC400 OBD-II ECU and harness and engine run in this 93 OBD-I SC400 was to plug in all connectors (which DO all plug right in from the 96 engine harness to the 93 car!!!) then jump 2 wires in one kick-panel connector to a B+ (power) source from an adjacent pin, turn the key, and hear it run as-is!
After we first got spark before I reconnected the coil wires to the distributors I undid the previous owner's fuel pump computer "12-volt mod" wiring change to the 93 harness and put that wiring totally back to stock before we finally tried to actually start the car with a functional ignition system and the fuel pump DID work properly through the stock 93 wiring with the 96 main ECU controlling the 93's fuel pump computer through its' totally unmolested 96 engine harness as expected.
Generic disclaimer, of course...
This project SC400 now starts and runs with only a very minor change being necessary to essentially just 3 wires in the 96 engine harness but it has yet to be driven so there may be other suprises I don't know about yet and I'll continue to post anything else I encounter until it's fully running and driving and making my buddy's 40+ mile 1-way work commute with no problems...
But considering the fact that the engine, transmission, engine harness, and main ECU were bought as a matched set and the car actually starts with such a minor wiring change I'll be suprised if there are any engine or tranny management issues at all...
*Initial reflections on the work in progress...
So the answer to the pre-immobilizer OBD-I to OBD-II swap being possible is that with a matched engine and tranny and engine harness and main ECU from a 96 OBD-II SC400 there is one power source configuration change that has to be modified with 4 power wires involved to mate it to an OBD-I 93 SC400 and everything else so far just plugs right in and works. I suspect that the 97 version would work about the same although I haven't seen a wiring book for it to compare, and I have a feeling that with the genuine Lexus wiring books for the appropriate year I could probably find a way around the 98+ key transponder security/immobilizer system with an aftermarket gadget of some kind and probably make one of those ECU's and its' matched engine harness and engine also start and run in the older model years too without much alteration to the harnesses unless Toyota/Lexus really changed connector shapes/sizes and such or really screwed with the wiring more than expected.
*Somewhat summarized status update...
Now that it's been verified that this setup WILL actually run with very minimal wiring alterations being needed, to complete this project I intend to essentially leave the 93 wiring fully untouched and cut and splice at 2 points in the 96 engine harness as my permanent solution which will allow me to recombine the split-load dual-feed EFI circuit in the 96 engine harness back onto its' own single 30A fuse as it would be in a 93 and to recombine the split-load dual-feed Ignition system circuit and power it with the 30A IGN fuse from this 93 model which are the same sized fuses that were used in 96 anyway... Essentially it's making the 96 harness match up with the 93 body wiring and relays and circuit fuses while retaining the revised split-load wiring of the 96 main ECU system...
To be a bit more precise on my intentions with pin numbers and such...
To re-route the secondary EFI B+ wire (EB2 pin 2 in 96) into the main EFI B+ wire at the EB2 connector (EB2 pin 3 in both years, black with red stripe and really thick) and tie EB2 pin 2 back into the igniter/coils/injectors circuit B+ wire in the 96 harness where it normally goes in a 93 is my goal.
I'll most likely get into the wire loom a few inches into the 96 engine harness side of the EB2 connector near the engine bay fuse box, then cut the EB2 pin 2 wire within the engine harness and splice the engine side of it to the EB2 pin 3 wire to recombine both parts of the EFI circuit back together within the 96 engine harness nearest to the source, and then tie the fusebox side of that cut pin 2 wire in the engine harness into the car's ignition system circuit as it would've been in a 93 which puts the ignition circuit back onto the correct relay and fuse for a 93.
I'll probably just connect the fusebox side pin 2 wire into the ignition circuit within the engine harness by attaching it to the the B+ wires of both igniters near their connectors and tie their B+ wires together for improved load capability back into the 96 harness as my primary IGN B+ feed point, then I'll complete the 96 engine harness' split IGN circuit by tying its' two IGN B+ wires together at the other end of the harness where they both meet which is the IJ1 pins 3 and 7 in the passenger kick panel that don't exist (are unused pins) in that area of a 93 SC400 at all.
Note that IJ1 pin 7 runs BOTH igniters and just the coil closest to the fusebox while IJ1 pin 3 runs the other coil over by the thermostat PLUS it also runs the entire set of of fuel injectors so combining those two pins at the IJ1 kick-panel connector is the easiest means of delivering B+ from the 93 Ignition Main Relay circuit to the 96 harness' divided parts of the full ignition circuit. So I need to be sure to make a solid electrical connection when combining those two pins as this configuration decision means that a failure of that connection would remove power from ALL injectors and ONE coil without any other signs of why the car shut down in that case... I could cut into the 96 harness at some other point and make that same type of connection but this is easier and cleaner and should be totally reliable with a good soldering of those two wires.
*Additional known remaining troubleshooting notes so far...
I haven't chased down the inoperative parking lights issue or the cause of the AIR-BAG light being on at all times even with no key in the ignition, either of which may or may not be related to the 96 engine harness, but those are both fairly low on the to-do list considering the car still needs hoses and fluids and such just to become operable...
So that's the latest at this point.
More to come after I finish those wire changes and we begin adding fluids and see if she'll move on her own for the first time since she showed up in my buddy's driveway 2 weeks ago which will apparently be the first time she's been drivable at all in years...
04-18-11, 08:07 PM
#14
4-17-2011
So for my permanent solution today with the negative lead of the battery disconnected I cut and spliced (soldered) the IJ1 pin 3&7 wires together near the connector in the 96 engine harness to combine the 96 B+ feed wire for the injectors and the coil that's near the thermostat to the main B+ feed wire for the igniters and the coil that's near the fusebox which recombines the entire ignition system within the 96 engine harness back into a single B+ power feed circuit as the 93 was designed for.
Then I cut the (3-pin fusebox plug) EB2 connector's pin 2 wire a couple inches from the connector on the engine harness side of it to remove the second 96 EFI B+ feed wire from the 93 Ignition Main Relay B+ feed, then TAPPED and soldered the engine side of that cut wire into EB2 pin 3's wire to combine the two 96 portions of the EFI circuit back together, then with an additional piece of similar but slightly bigger gauge wire to the wire gauge of EB2 pin 2 I spliced onto and soldered the connector side of the cut EB2 pin 2 wire and then TAPPED and soldered its' other end into the B+ wire (igniter connectors' pin 3) of BOTH igniters in their engine harness feed loom for theoretically improved current capacity.
Then we reconnected the battery and turned the key and the engine fired right up. Then we shut it down and checked for OBD-II trouble codes and there were none so we started it again, throttled it up a few times and then shut it down and checked for codes and again there were no trouble codes.
So for the remainder of this project before it can be declared complete, now we have to locate all necessary missing lines and hoses and reconnect all unattached vacuum, coolant, tranny, steering, and hydro-fan hoses and fill each system with its' proper fluid and install the primary cats so we can hang the exhaust and mount the two dangling O2 sensors, and double-check all engne mount and tranny mount and driveshaft bolts and such, and then try to actually drive it and see what issues, if any, we encounter next.
I'm not sure if the 96 engine harness having the TRAC system when the car doesn't will be an issue or not or what other suprise issues we may encounter but at least it does fire right up and run smooth on all 8 cylinders with the most minimal of changes to the 96 harness for the 93 SC at this point, YAY!
If any other suprise issues or trouble codes pop up that are related to this swap after we get the rest of the car back together and try to drive it I'll be sure and post those problems and whatever solutions we find for them but for now that's about it for this project and my buddy is very suprised and very happy with his new-to-him SC400 now.
So the answer is yes you CAN use a "matched set" 96 OBD-II SC400 transmission/engine/engine-harness/ecu in a 93 OBD-I SC400 and it drops right in and plugs right in and requires only a slight modification to the above noted 3-4 power wires in the 96 engine harness and then you should be good to go. Of course the 93 main ECU will NOT run the 96 engine, at least not through the 96 harness without a LOT of major wiring work and who knows what else, so if you do a swap like this for any reason be sure to get the engine harness and engine ECU that match the engine you're planning to install!
Personally I think I'd rather have the non-interference engine and lower compression on the older years, pre 95 1UZ's in the U.S. as I understand it, than the minor power increase and the down-sides that came with it but this is what I was given to work with and for the price I'm totally stoked with the results...
So now we've got 96 SC400 power and full 96 SC400 OBD-II diagnostics (*OBD-II Data Link connector installation and code reader required) in our 93 SC400 and it was damn near plug-n-play, oooooh...
So for my permanent solution today with the negative lead of the battery disconnected I cut and spliced (soldered) the IJ1 pin 3&7 wires together near the connector in the 96 engine harness to combine the 96 B+ feed wire for the injectors and the coil that's near the thermostat to the main B+ feed wire for the igniters and the coil that's near the fusebox which recombines the entire ignition system within the 96 engine harness back into a single B+ power feed circuit as the 93 was designed for.
Then I cut the (3-pin fusebox plug) EB2 connector's pin 2 wire a couple inches from the connector on the engine harness side of it to remove the second 96 EFI B+ feed wire from the 93 Ignition Main Relay B+ feed, then TAPPED and soldered the engine side of that cut wire into EB2 pin 3's wire to combine the two 96 portions of the EFI circuit back together, then with an additional piece of similar but slightly bigger gauge wire to the wire gauge of EB2 pin 2 I spliced onto and soldered the connector side of the cut EB2 pin 2 wire and then TAPPED and soldered its' other end into the B+ wire (igniter connectors' pin 3) of BOTH igniters in their engine harness feed loom for theoretically improved current capacity.
Then we reconnected the battery and turned the key and the engine fired right up. Then we shut it down and checked for OBD-II trouble codes and there were none so we started it again, throttled it up a few times and then shut it down and checked for codes and again there were no trouble codes.
So for the remainder of this project before it can be declared complete, now we have to locate all necessary missing lines and hoses and reconnect all unattached vacuum, coolant, tranny, steering, and hydro-fan hoses and fill each system with its' proper fluid and install the primary cats so we can hang the exhaust and mount the two dangling O2 sensors, and double-check all engne mount and tranny mount and driveshaft bolts and such, and then try to actually drive it and see what issues, if any, we encounter next.
I'm not sure if the 96 engine harness having the TRAC system when the car doesn't will be an issue or not or what other suprise issues we may encounter but at least it does fire right up and run smooth on all 8 cylinders with the most minimal of changes to the 96 harness for the 93 SC at this point, YAY!
If any other suprise issues or trouble codes pop up that are related to this swap after we get the rest of the car back together and try to drive it I'll be sure and post those problems and whatever solutions we find for them but for now that's about it for this project and my buddy is very suprised and very happy with his new-to-him SC400 now.
So the answer is yes you CAN use a "matched set" 96 OBD-II SC400 transmission/engine/engine-harness/ecu in a 93 OBD-I SC400 and it drops right in and plugs right in and requires only a slight modification to the above noted 3-4 power wires in the 96 engine harness and then you should be good to go. Of course the 93 main ECU will NOT run the 96 engine, at least not through the 96 harness without a LOT of major wiring work and who knows what else, so if you do a swap like this for any reason be sure to get the engine harness and engine ECU that match the engine you're planning to install!
Personally I think I'd rather have the non-interference engine and lower compression on the older years, pre 95 1UZ's in the U.S. as I understand it, than the minor power increase and the down-sides that came with it but this is what I was given to work with and for the price I'm totally stoked with the results...
So now we've got 96 SC400 power and full 96 SC400 OBD-II diagnostics (*OBD-II Data Link connector installation and code reader required) in our 93 SC400 and it was damn near plug-n-play, oooooh...
Last edited by zukikat; 04-18-11 at 08:28 PM.