please help. i am new to the supra and having a lot of trouble. i have a 1991 turbo, all stock. i just bought it and when the car is cold it idles well. when i accelerate to 2-3,000 rpms, engine misfires and runs rough seems to get rich, then stalls. i have checked timing and it's set to 10 degrees. no vacuum leaks. when this happens if i accelerate to wot. the car will level off and run ok for a little while. i have checked codes and i have a code 31. maf sensor circuit. i have replaced maf and it still continues, i even checked the connector and harness no faults seen. please help!!!! i don't know what else to do.
Help!!!! Please!!!
- Thread starter suprared89
- Start date
Boost leak, I'll bet. Check for cracks on your IC piping - especially the hose off the bottom of the turbo and the 3000 pipe to throttle body connection.
grim, i've checked all that and don't see any cracks or leaks. i am losing my mind with this car. it also seemed to be boosting on accel from low rpms. could it be the ecu???
Sure, but that's rather unlikely.
When these cars get old, the stock rubber bits get brittle, and crack. Happens to all of them. Then they leak some metered air under boost, meaning that the ECU is adding fuel based on lots more air going into the engine, making you run very rich... which makes your car misfire and sometimes stall.
I'd suggest building a boost leak tester, basically just a way to seal both ends of the IC piping and presuurize the system, then listen for the leaks. You'll find some, for sure.
You could also pull your codes in the hope that it's something else, but I'd be willing to bet money that you have boost leaks.
When these cars get old, the stock rubber bits get brittle, and crack. Happens to all of them. Then they leak some metered air under boost, meaning that the ECU is adding fuel based on lots more air going into the engine, making you run very rich... which makes your car misfire and sometimes stall.
I'd suggest building a boost leak tester, basically just a way to seal both ends of the IC piping and presuurize the system, then listen for the leaks. You'll find some, for sure.
You could also pull your codes in the hope that it's something else, but I'd be willing to bet money that you have boost leaks.
PS: Checking the pipe off the bottom of the turbo is rather difficult, but it has to be done. I've never seen one in good condition yet, unless it's been replaced since the car was new.
yea just looking at your hoses for boost leeks wont do it. safest thing would be to actually pull the hoses off, from accordian hose, turbo to ic ic to fender, fender to 3000 pipe, AND the coupler from the 3000pipe to tb. actually pull them off and flex the ends and you will find much more than the eye can see when on the vehicle, i thought i had a little edge crack on my accordian hose, when i pulled it off there were atleast 4 1 inchers that could only bee seen when i flexed the hose, boost pressure will open what you cant see. pull off you bypass valve and try to blow through it. if you can blow through it change it.