Having issues with USDM OBDII TT ECU mod
09-09-14, 06:48 PM
#32
gte & na-t
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It's extremely simple, would take a half hour at most to do, sans welding an ait bung into the IC piping. I strongly recommend not using the iat in the maf on an aristo ecu, it expects a heat soaked value and will run rich thinking there's cooler/denser air than there really is. But a gm iat in the IC piping would make it real simple since the wires are already in that area
yeah its just an IAT, its 2 wires to install a separate one. it is actually very simple.
almost everyone with a jdm tt ecu runs a safc at some point, if a shop has trouble doing that then its not a good shop.
honestly if wiring up a couple wires is too much then you should probably just get an aem ems v1 at this point and get it tuned for daily use (a shop should be able to get that going) and use the ecu you have now for your other purpose. funny thing is you will still need to wire in an IAT with the aem... there is no escaping that.
and its your usdm obd2 ecu that is likely the one that is being picky and causing the issues, so you can put however many safc's on there you want and try to adjust but you will just be fighting yourself and not fixing whats wrong. the safc cannot fix closed loop tune problems it just scales for injectors. i am also a little concerned the jdm ecu wont solve your problems either if there is a mechanical or sensor issue, but the jdm issue does tend to deal better with stuff not working since its much simpler.
I know this must be frustrating at this point, I still don't see why its not working as is since we know it can work with an obd2 ecu now thanks to buff's project. my only suggestion would be to double over the simple stuff. do you know anyone who is more DIY oriented than the shops to take a look at it.
do you have a wideband, can you take a video with the wideband showing where it freaks out in boost. these ecu's are supposed to dump fuel in when you get into real boost.
I am almost starting to think the ecu setup is fine and there is something wrong with the wastegate. you should not hear air wooshing and the car going no where generally speaking.
I would say take it off and check it (its a pain), or at least check the vac lines to the wastegate and make sure the boost controller is inserted the right way. I have definately seen people put them backwards and it creates a vac leak.
on the same note, what vacuum are you showing at idle warmed up. should be -18 to -20 inhg/mm on a healthy na-t
another question, where is the passenger side valve cover breather hose going to. it looks like it goes down by the downpipe or something?
almost everyone with a jdm tt ecu runs a safc at some point, if a shop has trouble doing that then its not a good shop.
honestly if wiring up a couple wires is too much then you should probably just get an aem ems v1 at this point and get it tuned for daily use (a shop should be able to get that going) and use the ecu you have now for your other purpose. funny thing is you will still need to wire in an IAT with the aem... there is no escaping that.
and its your usdm obd2 ecu that is likely the one that is being picky and causing the issues, so you can put however many safc's on there you want and try to adjust but you will just be fighting yourself and not fixing whats wrong. the safc cannot fix closed loop tune problems it just scales for injectors. i am also a little concerned the jdm ecu wont solve your problems either if there is a mechanical or sensor issue, but the jdm issue does tend to deal better with stuff not working since its much simpler.
I know this must be frustrating at this point, I still don't see why its not working as is since we know it can work with an obd2 ecu now thanks to buff's project. my only suggestion would be to double over the simple stuff. do you know anyone who is more DIY oriented than the shops to take a look at it.
do you have a wideband, can you take a video with the wideband showing where it freaks out in boost. these ecu's are supposed to dump fuel in when you get into real boost.
I am almost starting to think the ecu setup is fine and there is something wrong with the wastegate. you should not hear air wooshing and the car going no where generally speaking.
I would say take it off and check it (its a pain), or at least check the vac lines to the wastegate and make sure the boost controller is inserted the right way. I have definately seen people put them backwards and it creates a vac leak.
on the same note, what vacuum are you showing at idle warmed up. should be -18 to -20 inhg/mm on a healthy na-t
another question, where is the passenger side valve cover breather hose going to. it looks like it goes down by the downpipe or something?
Why don't you take it to Sp and let Larry fix it for you at this point?
Its really easy, I wish you were couple hundreds mile away from me, because I will drive down and fix it for you free of charge just for the hell of it.
Go to the shop and pick up your car.
09-10-14, 11:51 AM
#33
I think I may have thought of something thats easy to miss.
by where the stock coil is, is a white plug with 2 wires and a small box plugged into it. this is the ignition noise filter. when removing the stock coil one may be tempted to remove this, but it needs to stay.
it looks like this but instead of on the ignitor its by the stock coil
Not sure if this is a sc300 coil but the silver thing take off the bracket and leave it plugged into the harness when removing the stock coil.
this can cause all sorts of ignition issues if removed.
by where the stock coil is, is a white plug with 2 wires and a small box plugged into it. this is the ignition noise filter. when removing the stock coil one may be tempted to remove this, but it needs to stay.
it looks like this but instead of on the ignitor its by the stock coil
Not sure if this is a sc300 coil but the silver thing take off the bracket and leave it plugged into the harness when removing the stock coil.
this can cause all sorts of ignition issues if removed.
09-10-14, 06:42 PM
#35
yeah I know it can run without it but I am just listing out everything it can be. another remember removed his and reports car is working fine but still should be on the car.. lol. maybe obd2 is more sensitive or something really running out of ideas here.. 
09-15-14, 01:16 PM
#37
gte & na-t
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Ali - his car is 97 it has the same O2 sensor setup as the Mk4 Supra , he has a secondary cat in the midpipe and that pipe has a 2 bolts style 02 sensor in it that run through the floor board and plugs inside the car by the radio.
All 96-97 SC have that sensor all the way up to 2000.
All 96-97 SC have that sensor all the way up to 2000.
09-16-14, 09:38 AM
#38
yeah stock he should have 3 sensors. 2 on the manifold and 1 downstream on the midpipe. I know its a similar setup as the mk4 supra but when installing the downpipe one has to use both those 2 sensors that were on the manifold before. maybe if there wasn't 2 bolt on spots on the downpipe some mechanic may have left one of them off I was thinking.
The JDM ecu I just say pick 1 and leave the other as it only uses 1 main sensor, but USDM you have to use both of the main manifold ones that were there, it uses both, both have to be in downpipe right after turbo.
yes there will be the third sensor on the midpipe should already be there on that car but the main 2 is what will cause it to run funny if one of those is not plugged in.
The JDM ecu I just say pick 1 and leave the other as it only uses 1 main sensor, but USDM you have to use both of the main manifold ones that were there, it uses both, both have to be in downpipe right after turbo.
yes there will be the third sensor on the midpipe should already be there on that car but the main 2 is what will cause it to run funny if one of those is not plugged in.
09-18-14, 06:43 PM
#39
Lexus Test Driver
Thread Starter
Ok, guys, so I've been busy with work and not really checking up on the car this past week, but i stopped by the shop today, and here is what we have.
-The car starts up and idles perfect. Nice and quiet and not high like it used to. The timing and TPS was set and double checked and its great.
-There is no CEL and it seemed to be ok, however, i took the car for a spin and it backfires like crazy low in the rev range, and by the time the motor is at 4k rpm the car just doesnt pull at all and goes super rich. It just dumps fuel all at once, and the car goes nowhere. I immediately came back and parked it, and left the shop. The mechanics seemed stunned because they swear the car ran fine before i got there. So yeah, I passed them along all the insight you guys gave me, but now it seems like the car runs worse. Before it was at least driveable, now it just smells like fuel, and drives like crap.
-The car starts up and idles perfect. Nice and quiet and not high like it used to. The timing and TPS was set and double checked and its great.
-There is no CEL and it seemed to be ok, however, i took the car for a spin and it backfires like crazy low in the rev range, and by the time the motor is at 4k rpm the car just doesnt pull at all and goes super rich. It just dumps fuel all at once, and the car goes nowhere. I immediately came back and parked it, and left the shop. The mechanics seemed stunned because they swear the car ran fine before i got there. So yeah, I passed them along all the insight you guys gave me, but now it seems like the car runs worse. Before it was at least driveable, now it just smells like fuel, and drives like crap.
09-18-14, 09:12 PM
#41
Lexus Test Driver
Thread Starter
Adjusted the cam angle sensor, Tps, dialed in timing with a timing light and obd scanner, checked every part associated with the na turbo conversion, checked coil packs and wiring, checked adjusting screw on throttle body, checked for boost leaks with pressure tester
09-19-14, 05:11 AM
#42
Get a new shop. They don know what they're doing, and are taking you for a ride. Cam angle sensor doesn't really exist, it's in the distributor, it's a fixed setup, no adjustment. Unless they're calling the distributor the CAS, but that sounds like some Nissan bs. And they said they locked in timin with a light, that would be by adjusting the distributor. So saying there's a distributor and cam angle adjustment is bs.
09-19-14, 05:19 AM
#43
gte & na-t
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^^^^That's exactly what I told him, I asked him to get a gopro and actually record what the car is doing.
Go get your car back take it home and try to fix it on your own or Just take it to SP.
You are just chasing your tail...Those guys don't know what they are talking about, it's something really simple.
Go get your car back take it home and try to fix it on your own or Just take it to SP.
You are just chasing your tail...Those guys don't know what they are talking about, it's something really simple.
09-30-14, 08:17 PM
#44
Lexus Test Driver
Thread Starter
ok, guys so this final shop that has had my car for the last couple months has no clue whats going on with my car. Has anyone actually successfully run an obdii car with a usdm obdii ecu? the conclusion this shop came to is that i need an engine management system and a tune. they say it needs a turbo harness, or a gte head or some other BS they are making up. I just dont have the resources anymore to take this car to any other shops. I will try to pick up the car tomorrow, and i will shoot a video with my phone and try to post it up here. please stay tuned.
10-01-14, 05:07 PM
#45
Lexus Test Driver
Thread Starter
Ok here are the videos. Not very good. I will try to shoot some later when its dark so you can see the revs and speeed and hopefully wideband better. The car idles fine and runs ok under 3k rpm, but past that nothing happens. Loud whooshing sound and the car just doesnt want to rev and does not accelerate. Then there is loud backfiring, because the car is dumping fuel like crazy.