Ali SC3

iTrader: (10)

From what I researched the TT maf is the same for obd1 and obd2. on a supra TT usdm, you can unplug the obd1 ecu and plug in the obd2 ecu and drive away without any issues or changing a thing in the engine bay. you only have to do wiring for the obd2 port to work cause well an obd1 tt supra does not have an obd2 port and a ground for the o2 sensor.
http://www.supraforums.com/forum/sho...2-ECU-Upgrade&

One thing I see that is not correct is that the idle speed is off for a factory ecu and intake manifold.
where your idle is at now kind of says that the ecu is not idling down properly for some reason.
it should settle down to 650 rpm when warm with a/c off, and around 800 with the a.c turned off.
if you reset everything and give it a chance to learn and it does not idle there, then something is off.
If its the tps it will affect the how the car boosts, as in it will not boost well, also its not uncommon to get misfires with tps problem.
on that obd2 parameter screen, can you see that the tps is responsive?

I am not sure if cylinder 1 is locked at 10 just cause the diagnostic stuff is on there, if that is the case verify with a timing light if you have one when the scanner is on that its 10 on the crank also.

also I would remove the manual boost controller just connect the 2 vac lines together and see how its acting normally off the waste gate spring.
also bypass the vsv for the fuel pressure regulator which is that blue vsv, just connect the 2 vac lines there together also or connect the one going into the vsv straight to the fpr. when you hot start the car it will open the fpr to open air to give more fuel, but it doesn't know you have a turbo now. I would just bypass this entirely if the tt ecu is not controlling this properly and I do not think a tt motor even has one, then the map sensor would see open air when it should be seeing pressure. while this is a maf car I would say its possible it maybe could still effect the ecu.

I also remember something about the 96 or 97 sc300 having a different pin for grounding the maf. that could have something to do with it potentially I would verify the maf ground is going to the right pin for the supra ecu.

99SC42

iTrader: (44)

Yes wiring on the maf between 96-97 IS different..

Make sure every wire is in the right pin, do you have a 97 wiring diagram?

I will overboost a little that's normal because of the ****ty manifold and depending on the weather.

I am 100% sure if you pull the tt ecu off and maf and then run an aristo ecu your problem will be solved.. but you have to deal with emissions.

Ali SC3

iTrader: (10)

I know man its these maf ecu's that are sensitive. have you sprayed the maf down with maf cleaner. those things are always so touchy when they are dirty.

99SC42

iTrader: (44)

This is why I hate maf sensor setup lol, specially on the vvti setup...

My GS300 had a maf problem I was chasing for over 6months, I had all types of codes EXCEPT a maf code lol, finally decided to try a spare sensor I picked up from Bart and Bam I was back in business!!

The vvti gte is the worst...I done a swap in buddy's car and got to a point where I was pulling my hair out.. reset the ecu a few times and now its been great.

myLEXsc400

I will be attempting this.

When I have a chance, I will. The car is at the shop so I would have to go there and do it. I imagine I have to upload to YouTube first, correct?

Yes, Walbro 255

Noted. I just sent all that info to my mechanic.

Whoa, so the MAF itself is the same but the wiring is different? No I do not have the diagram. Where can i find one? So its wired differently to the ECU?


No I never sprayed the MAF. I actually have a guy who will sell me a MAF off a 97 USDM TT Supra for cheap so I might as well buy it and try it.

Ali SC3

iTrader: (10)

maybe its worth trying a spare maf then. you can even try the stock one it should run it will just read more load so it will run rich but could work I don't really know for sure. a SC400 or LS400 96+ maf is probably close in size to a TT one also as suggested.
the TT type of mafs can be cleaned with the regular maf cleaner, just shoot it down with the stuff and let it dry out completely.

the place where the maf wire ground goes into the ecu is different on a 96 and maybe some 97.
I would think that it would not drive normally out of boost though if this was the problem.
maybe the coils you have are sparking weak for some reason, make sure ignitor is grounded properly.

myLEXsc400

So wait, technically all i would have to do is swap in the usdm ecu come emission time, and plug in the Maf? Sounds tempting....

99SC42

iTrader: (44)

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Yeah that's all you have to do

myLEXsc400

I imagine i would have to re-wire some things to make it work, right? Also, weren't all aristo's automatic? Would it run right since my car is a stick? Is it as simple as just unplugging the MAF (without taking it out), and then plugging it back in when i need to go back to the usdm ecu?

99SC42

iTrader: (44)

It will runs just fine.

What injectors are you running?

You just need to wire the iat sensor and you are done..

I've put aristo ecu on a bunch manual cars with gte swaps works fine.

I was going to come CHi2K but my Friend couldn't make it so I canceled the trip I would've Pm you to help you figure this out.

Ali SC3

iTrader: (10)

He is on 550's, you will need to pick up a safc, doesn't need to be fancy even the first generation will work for scaling injectors.

well if you already wired up a JZ map on your current harness then there is not much wiring at all to swap to the JDM ecu.
you would need an IAT somewhere or just leave the maf plugged in and unplug the maf pin at ecu, then the iat will work from the maf still.

only other thing I can think of is that you would need to swap to 440's when you swap ecu's or have a safc or other piggyback to pull some fuel.

the aristo ones are all auto, and I have run it with a manual transmission on my car before. you can also get a JDM supra 6 speed ecu that is what I swapped to now. a little harder to find but they do come up.

so add Intake sensor or reuse maf's intake sensor, add piggyback or swap injectors, and you can swap out the ecu.
if you want to go back and forth I would just pull the maf pin, add the JDM ecu with a piggyback.
then when you go back to usdm all you have to do is put the maf pin back in and swap ecu.. I think you wouldn't even have to remove the piggyback it can stay for both ecu's the USDM will not care if there is scaling on the map sensor, in fact it will raise how much boost you can run a little before fuel cut on both ecu's.

99SC42

iTrader: (44)

See Ali- they can use the maf as iat sensor but since this thing is not running properly I didn't wanna make it hard on them. So I would just T into the maf wires to hook up the IAT sensor and be done with it.

I would keep things Simple till you get it running properly and then start to try different stuff.

Yeah with 550 you will need a fuel controller like Ali said.

myLEXsc400

Ok, so its not that simple then.
But If I get an SAFC, then I might as well keep my usdm ecu because I can just adjust for everything there....

Vrank

iTrader: (4)

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

Ali SC3

iTrader: (10)

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?