2jzGTE SCs - The Siblings of my Supra MKIV Toys
No problem buddy !!! You are like just 40 miles away .
01-12-14, 10:19 AM
#2087
Non VVTi 2jzgte Lexus SC Engine Harness Build - Question & Answers
Q) My harness was done by a "pro" but I am using a jdm supra six speed ecu instead of an ARISTO ecu. I already had the harness made with the needed relay wired in the a/c circuit but it still never worked. Is it because I am using the wrong ECU ? . Is that hyper sensitive relay really needed with the jdm or usdm SUPRA MKIV ECU? Also I was told by the "pro" to cut the relay out and cap off the wires on the 12v feed and connect the other to each other. But now I'm going pro efi and need to figure out hot to get that going so I'll wait for that part I guess.
Sorry to hear that buddy . I hope I am understanding what you are saying ... that is , you bought an harness with that hypersensitive relay already incorporated and still your AC doesn't work . At the same time , you took the relay out just to bring the wiring back to original state before the relay was added and still your AC won't work .
Hmmm .. I have a good solution for you ! Give me that freaking SC300 and I can live without an Air Condition and you won't have any problem with it anymore....
. Everyone on this forum is dying to have the kind of car you have no doubt.
Kidding aside , let's go through your questions ..
a) Am I using the wrong ECU ? Well , your car runs well .. so yes and no
. NO for everything since your car runs well and YES for the AC since the AC do not work. The solution I mentioned above was for the Aristo 2jzgte ECU. BUT let us investigate this further with regards your ECU.
b) Is that hyper sensitive relay really needed for the JDM or USDM MKIV ECU ? Based on what you have said , when it was connected , you had no AC . When you took it out , you still have no AC. So based on what you said , probably not . Not sure for now so we have to investigate further your case.
c) You think if I use a USDM MKIV ECU , assuming I have the right injectors / resistor pack and wiring will my AC work with that relay ? No it will not and I will tell you why I believe it will not.
The JDM and USDM MKIV cars basically has a lot of similarities in their wiring diagrams and circuitries. I have just look at their Air Conditioning Wiring Diagrams and basically are the same so since you are currently using a JDM MKIV ecu and AC didn't work with that relay , I honestly doubt it will work even with a USDM MKIV ecu. Again, needs further investigation.
These are my initial thoughts on why you have no A/C whether with or without that relay. I will further investigate though I would like you to do something for me to confirm that the other parts of your A/C system is good.
Maybe :
a) You got a bad connector / wirings for Pin 23 and Pin 34 of the 40 pin Connector or mechanical problems in nature like bad pressure switch, shorted or open clutch wiring , stucked up or bad comppressor or not enough freon.
b) Maybe the relay which is activated when pin 23 is grounded by the ECU is bad . That relay provides the actual path for electricity to flow towards your A/C magnetic clutch.
c) On the JDM and USDM MKIV ECU , pin 34 of the 40 pin Connetor , which is the A/C request signal , based on the diagrams goes through another computer before it goes to the main Computer . So maybe , there is another process going on in their circuitries before the circuit on Pin 23 of the 40 pin Connector is grounded by the ECU which in turn should provide power to a coil for a relay switch which allows current to flow to the A/C magnetic clutch thus turning on the compressor.
This is why I want you to do this for me please . Get an SPST (single pole single throw) Toggle switch. Connect one port to the ground . Disconnect Pin 23 from the 40 pin ECU Connector. Connect the other port of the toggle switch to that Pin 23 which you just disconnected from the 40 pin ECU connector. Start your car , turn on that toggle switch and let me know if your AC is working. If it does, you know there is nothing wrong in your A/C system and that relay which allows current to flow to the magnetic clutch . IF it doesn't and that relay along pin 23 which when energized allow current to flow to the magnetic clutch is not bad , then your problem is not on the wiring . Another way , if you don't have a toggle switch , when you have taken out that pin 23 from the 40 pin Connector , while your car is running connect that pin to ground and if there is nothing wrong mechanically with your A/C system , you should hear that compressor kick in and have cold air.
Let's do that , start from that side of the A/C system and move or probe backwards , so we can determine what is the real problem why you have no A/C. We will nail down the culprit
. Finding what the real problem is easy. In fact if that Toggle Switch will get your AC running then you have a primitive way of turning the AC on right now.. hehehe..It ain't optimal but you know your AC is working. I said it is not optimal because everytime an AC request is done, the corresponding engine speeds are supposed to be manipulated by the ECU so your engine wont die specially when you are idling.
Sorry to hear that buddy . I hope I am understanding what you are saying ... that is , you bought an harness with that hypersensitive relay already incorporated and still your AC doesn't work . At the same time , you took the relay out just to bring the wiring back to original state before the relay was added and still your AC won't work .
Hmmm .. I have a good solution for you ! Give me that freaking SC300 and I can live without an Air Condition and you won't have any problem with it anymore.... . Everyone on this forum is dying to have the kind of car you have no doubt.Kidding aside , let's go through your questions ..
a) Am I using the wrong ECU ? Well , your car runs well .. so yes and no
. NO for everything since your car runs well and YES for the AC since the AC do not work. The solution I mentioned above was for the Aristo 2jzgte ECU. BUT let us investigate this further with regards your ECU.b) Is that hyper sensitive relay really needed for the JDM or USDM MKIV ECU ? Based on what you have said , when it was connected , you had no AC . When you took it out , you still have no AC. So based on what you said , probably not . Not sure for now so we have to investigate further your case.
c) You think if I use a USDM MKIV ECU , assuming I have the right injectors / resistor pack and wiring will my AC work with that relay ? No it will not and I will tell you why I believe it will not.
The JDM and USDM MKIV cars basically has a lot of similarities in their wiring diagrams and circuitries. I have just look at their Air Conditioning Wiring Diagrams and basically are the same so since you are currently using a JDM MKIV ecu and AC didn't work with that relay , I honestly doubt it will work even with a USDM MKIV ecu. Again, needs further investigation.
These are my initial thoughts on why you have no A/C whether with or without that relay. I will further investigate though I would like you to do something for me to confirm that the other parts of your A/C system is good.
Maybe :
a) You got a bad connector / wirings for Pin 23 and Pin 34 of the 40 pin Connector or mechanical problems in nature like bad pressure switch, shorted or open clutch wiring , stucked up or bad comppressor or not enough freon.
b) Maybe the relay which is activated when pin 23 is grounded by the ECU is bad . That relay provides the actual path for electricity to flow towards your A/C magnetic clutch.
c) On the JDM and USDM MKIV ECU , pin 34 of the 40 pin Connetor , which is the A/C request signal , based on the diagrams goes through another computer before it goes to the main Computer . So maybe , there is another process going on in their circuitries before the circuit on Pin 23 of the 40 pin Connector is grounded by the ECU which in turn should provide power to a coil for a relay switch which allows current to flow to the A/C magnetic clutch thus turning on the compressor.
This is why I want you to do this for me please . Get an SPST (single pole single throw) Toggle switch. Connect one port to the ground . Disconnect Pin 23 from the 40 pin ECU Connector. Connect the other port of the toggle switch to that Pin 23 which you just disconnected from the 40 pin ECU connector. Start your car , turn on that toggle switch and let me know if your AC is working. If it does, you know there is nothing wrong in your A/C system and that relay which allows current to flow to the magnetic clutch . IF it doesn't and that relay along pin 23 which when energized allow current to flow to the magnetic clutch is not bad , then your problem is not on the wiring . Another way , if you don't have a toggle switch , when you have taken out that pin 23 from the 40 pin Connector , while your car is running connect that pin to ground and if there is nothing wrong mechanically with your A/C system , you should hear that compressor kick in and have cold air.
Let's do that , start from that side of the A/C system and move or probe backwards , so we can determine what is the real problem why you have no A/C. We will nail down the culprit
. Finding what the real problem is easy. In fact if that Toggle Switch will get your AC running then you have a primitive way of turning the AC on right now.. hehehe..It ain't optimal but you know your AC is working. I said it is not optimal because everytime an AC request is done, the corresponding engine speeds are supposed to be manipulated by the ECU so your engine wont die specially when you are idling.
Last edited by gerrb; 01-13-14 at 06:31 AM.
01-12-14, 11:09 AM
#2089
The wire you are talking about that you were asked to connect back together, I assume will be pin 34 of the 40 pin ECU Connector. Without any relay , that wire should go to a body plug which is white .. It's body plug II1 pin 5.
01-12-14, 11:12 AM
#2090
Did they install the same Reed Relay in your harness ? IF not , can you take pictures of the relay and the wirings in that area showing which you connected too ? Send them to this phone 770 6963345 or post them here. If yes, just follow the diagram I drew .. but start from Figure B .. remove the two wires from the Reed Relay and join them together.
The wire you are talking about that you were asked to connect back together, I assume will be pin 34 of the 40 pin ECU Connector. Without any relay , that wire should go to a body plug which is white .. It's body plug II1 pin 5.
The wire you are talking about that you were asked to connect back together, I assume will be pin 34 of the 40 pin ECU Connector. Without any relay , that wire should go to a body plug which is white .. It's body plug II1 pin 5.
01-12-14, 11:32 AM
#2092
Got you ! No worries , whenever you can . Yes the body plugs are under the glove box. IF you are facing the ECU which is bolted down your passenger footwell , all those body plugs are plugged to the side of that footwell. Reason why they call them body plugs.. they are plugged on the receiver plugs which are fastened or bolted on the body of the car.
01-12-14, 11:36 AM
#2093
Ok I think I remember what I did and it's so newbish and dumb lol.
When I cut the relay out it was connected to pin 34 with two wires and b+at the ecu with two tees from relay. I think I cut it all out and capped both ends at the ecu so I capped pin 34 wire and b+ wire at the ecu and connected the other ends together so I joined two wrong circuits meaning the b+ wire and pin 34 wire going back to harness lol wow I'm dumb
When I cut the relay out it was connected to pin 34 with two wires and b+at the ecu with two tees from relay. I think I cut it all out and capped both ends at the ecu so I capped pin 34 wire and b+ wire at the ecu and connected the other ends together so I joined two wrong circuits meaning the b+ wire and pin 34 wire going back to harness lol wow I'm dumb
01-12-14, 12:01 PM
#2095
Ok I think I remember what I did and it's so newbish and dumb lol.
When I cut the relay out it was connected to pin 34 with two wires and b+at the ecu with two tees from relay. I think I cut it all out and capped both ends at the ecu so I capped pin 34 wire and b+ wire at the ecu and connected the other ends together so I joined two wrong circuits meaning the b+ wire and pin 34 wire going back to harness lol wow I'm dumb
When I cut the relay out it was connected to pin 34 with two wires and b+at the ecu with two tees from relay. I think I cut it all out and capped both ends at the ecu so I capped pin 34 wire and b+ wire at the ecu and connected the other ends together so I joined two wrong circuits meaning the b+ wire and pin 34 wire going back to harness lol wow I'm dumb
Ok. Get that pin 34 wired properly first and see if your AC is working . Then we go from there. Let's isolate where the problem is. Send me text messages anytime. No problem ! If I am busy I might not answer right away but will surely do
. This statement doesn't sound right .."When I cut the relay out it was connected to pin 34 with two wires and b+at the ecu with two tees from relay." If you check the diagram I drew and posted only one wire should be connected to pin 34 coming from the relay . At any rate please verify.
Without a relay , Pin 34 of the 40 pin ECU connector goes to pin 5 of body plug II1 which is a white connector . Make sure you have a good connectivity between the two . Pin 5 of Body Plug Connector II1 will then go to the HVAC control unit through the HVAC Control Unit plug IR2 pin 10 . I will post a picture here later.
Last edited by gerrb; 01-12-14 at 12:12 PM.
01-12-14, 01:32 PM
#2097
Non VVTi 2jzgte Lexus SC Engine Harness Build - Post # 43
E) Body Plug II1 with 12 pins - White
unlocking and removing is just like the big gray Aristo plug
F) Let me call this Body Plug Small (for now) with 6 pins - White
unlocking and removing is just like the big gray Aristo plug
unlocking and removing is just like the big gray Aristo plug
F) Let me call this Body Plug Small (for now) with 6 pins - White
unlocking and removing is just like the big gray Aristo plug
Last edited by gerrb; 01-29-14 at 03:22 AM.
01-12-14, 02:35 PM
#2098
Yes .. without the relay those two wires from pin 34 should be connected again. And you remove the relay with the two tees from pin 32 so you avoid any shorts . I believe that was the instruction given to you by whoever did you harness.
01-12-14, 03:12 PM
#2100
Non VVTi 2jzgte Lexus SC Engine Harness Build - Post # 44
Before we go ahead , at this point , this is what I am expecting more or less from your harness .. what we have done so far.
Aaron's harness so far.. have taken out all those VSVs and plugs not needed
Red Mamba 2 harness so far... unfortunately I have no more corrugated flexible hose at this time. It is like stock since I have all the VSVs still on the harness
Aaron's harness so far.. have taken out all those VSVs and plugs not needed
Red Mamba 2 harness so far... unfortunately I have no more corrugated flexible hose at this time. It is like stock since I have all the VSVs still on the harness
Last edited by gerrb; 01-29-14 at 03:23 AM.