myLEXsc400

Hello community. Those of you who check out Ali's TT ECU mod thread may have seen my annoying posts asking for guidance with my car over the last year. I've been advised to start a new thread so that I don't jack that one more, so here it goes.

Some background on my car
-1997 SC300, factory W58 trans with Southbend Stage 2+ clutch.
-SP63 turbo (Precision Turbo by Sound Performance)
-IS300 coilpacks
-laser cut iridium plugs
-1jzgte MAP sensor
-MAF from 94 Supra Turbo
-ECU from a 1997 USDM M/T Supra Turbo
-Tial QR recirculating BOV with 8lb spring.
-Wastegate with 7lb spring i believe
-Manual boost controller for 10psi
-OBDI lower runners
-550 injectors

So when I first decided to do the mod, i took it to a shop that wired in the ecu, did the COP conversion, and when the mechanic said the car was "done", it would shut off going back to idle after boosting, and the car would hesitate and go pig rich at WOT. He convinced me to recirculate the BOV bc he thought it would fix the issue, but it didn't. He told me he can't do anything else, and that if I want my car to run right i need a standalone and a tune.
I did not give up on this mod because i needed my car to pass emissions in Chicago, so I took it to another shop where they re-did some shoddy wiring and and told me to change my BOV, did a whole bunch of boost leak tests, changed out my lower runners so that the injectors would seal, and supposedly set the timing, and TSP (they didn't), and my car ran well for a bit. It wouldn't shut off on me anymore but it would still hesitate going into boost. My CEL came on a couple days later with a misfire it ran ok without the CEL on for less then a week. I had it dynoed when it was still running ok and then parked it, and the next day in the evening i started it up and the CEL is on again. It smelled like fuel again. I ran the codes and they are
P0300
P0302
P0303
P0306
So there is a random misfire, and a misfire on cylinders 2,3, and 6.
This was the second time these codes have come back within a few weeks.
So i then decided to take it to a 3rd shop so maybe they can finally fix this junk. They checked my coilpacks, replaced my spark plugs, redid all the vaccum lines (replaced them with new ones), and cleared the codes. The car ran OK for the first day I got it back, and then the same codes came back. The car makes a loud whooshing air sound between 3000-4500 rpm and just does not accelerate during that time. Then it pulls past that from 4500-6000 at which point whats the point? I lost in a stop-light drag race with my dad's stock Chevy Colorado Xtreme. Thats embarrasing. Oh, and the boost spikes at 12psi for some reason even though my MBC is supposed to peg it at 10psi. IDK whats wrong with this car...... Im so broke because of it.So i took the car back and they still can't figure it out. They set the timing correctly this time, adjusted the tps, and the misfire hasn't come back yet, but the car still hesitated going into boost, and dumps fuel at WOT. Not only that, but at 4k when the boost really starts to kick in, the computer starts dumping fuel like its saving the motor from detonation. It runs great up until then but when it hits 4k it starts to break up and the boost is creeping and spiking to up to 14psi. Which is not normal. The car also idles at at 800 or more.

Here are some pics











So If anyone might know why my car is acting like this, please chime in. Any and all help will be greatly appreciated. Thank you all in advance

99SC42

iTrader: (44)

Ok first you need to get a maf sensor that matches with you 97 ecu.

I am sure if you had a 94 ecu , it would have worked no problem.

myLEXsc400

I have been told that any year 2jzgte MAF would work. I really hope that this is the issue. Now to just locate a 97 GTE MAF

myLEXsc400

So upon further investigation, the main part number for all 93-98 supra turbo's sold in the US is the same. However, the number on the bottom is different by one digit. would this make a difference?

Here is what I have


What i can buy off ebay. apparently from a 98 turbo

187

the sensor that I bought froma obd2 buy is 011, no way to tell without comparing voltages I would guess. Did you try and use the stock maf by any chance? its only slightly smaller then the TT

99SC42

iTrader: (44)

P0300
(DI-204 )
Random / Multiple Cylinder
Misfire Detected
P0301
P0302
P0303
P0304
P0305
P0306
(DI-204 )
Misfire Detected
- Cylinder 1
- Cylinder 2
- Cylinder 3
- Cylinder 4
- Cylinder 5
- Cylinder 6
So Check these below:
Ignition system
Injector
Fuel line pressure
EGR
Compression pressure
Valve clearance not to specification
Valve timing
Mass air flow meter
Engine coolant temp. sensor

http://www.97supraturbo.com/1997%20S...ics-Engine.pdf

myLEXsc400

Yeah, I wonder if there is a big difference and if maybe this is whats causing my car to run bad.... But I don't know if i should just go ahead and shell out $150 just to see. I guess maybe I can just post it up back for sale if it does nothing... I do have the stock MAF but never though of running it with my setup because I just figured it wouldn't work right.

The car does not have a CEL on anymore, and to my knowledge it is not currently misfiring. I believe it was misfiring before because the timing was not set correctly. It just has that boost spiking problem and hesitation where nothing happens going into boost.

That link is great though. Lots of useful info. Now I just need to dedicate some time and read through it.

myLEXsc400

So, do you guys recommend I buy the MAF from Ebay from the 98 turbo?

187

are you sure your not hitting boost cut at like 4000rpm? whats the spike doing? If you peg it to 14 its going to stop you from revving upwards.

Have you tried running just on the waste gate spring?

It may be worth trying the stock maf, its only about 1/4 inch difference, if anything the computer will correct for the flow and you should be able to tell if its the maf or not.

I talked to Ali about this before and he wasn't totally against trying it but it may mess with the afrs slightly I would guess until it learns.

I would only buy the maf as a last ditch effort, If it really wasn't working I don't think the car would be idling correctly.

Vrank

iTrader: (4)

Different engine, but I feel 99% certain that I've run both part number supra meters on my 1j vvti, as well as the stock 1j/obd2 ls400 (same p/n) all with zero noticeable difference in driveability/parameters from logs. So if there's a 96-2000 ls400 at your local pick and pull you could try that for cheap depending on how y'all have it for pricing out there

myLEXsc400

I don't think its hitting boost cut at 4k, but on second thought its something to look into. what might cause it to do that though? i don't think i have the stock MAF anymore. but i am really hoping that the maf is the culprit, since I'm an obdii car and the obdii ecu is a bit different, it might want the maf to be from the later cars too. i really don't know if there is a difference or not between the mafs with the secondary part numbers being off by a digit, but at this point, i might as well just buy the other maf, and sell it if it makes no difference. its not that the maf isn't working, it just might not be working perfectly with the ecu i have.

I did run the car off the wastegate when i first got the car turboed, and the boost never went past 7psi, and the car felt really slow. but at that time the car would also shut off after being boosted whenever i pressed the clutch, so idk. this thing never ran right. and it had the same issue with hesitation.

yeah, its not worth my aggravation to do do that, i might as well just buy the newer gte maf and see if it makes a difference. do you think that because obdii is a more complicated ecu it might actually make a difference in my car? i know the primary part number is the same, but that secondary one has got me curious. i really dont know WTH is wrong with this car.

myLEXsc400

is it possible that the ECU might be faulty?

187

I don't think your ecu is the problem, try the waste gate with no boost controller and see if you can get it going at 7 psi past 4k.

If either of your parts (ecu or maf) were faulty I would expect more problems especially just idling, it seems like going into boost is the problem hence why I was mentioning why you should try just the waste-gate.

99SC42

iTrader: (44)

OK Do you have a gopro? or can you borrow a go-pro and show us what the car is doing while you are driving?

That would be the best bet before you start buying parts and changing stuff on it.

What would be very helpful

187

Also have you installed a new fuel pump?