tikkis

Hi!

I have a problem with my JDM STI. When the engine is warm, idle is almost normal but when cold, the car barely runs. Revs are somewhere around 200 and below. If I drive around a bit the car starts to idle smoother, but if I let it idle a while revs start to drop again. CEL indicates error code 23 which is MAF, but I changed that and there was no noticeable difference.

At first the engine light would turn on but when I messed around with MAF sensor wiring all was well again. Then there was some bearing issues and the engine was taken apart and rebuild. Now the light stays on no matter what. The wiring seems to be OK and If I plug the MAF off the car stalls so ECU probably sees at least something.

Car won't rev properly past 4000 so I'm guessing some kind of limb mode? Last time I tried to start it with MAF not plugged in I think it didn't idle too good either. Isn't it supposed to use default map when MAF is out so it should have idled a bit better?

I also tried to reset the ECU but there was no indication that it even happened and I noticed no difference. It kept blinking the CEL 23 through the process. As the reset included some full/half throttle, I thought that maybe the throttle position sensor was busted but I tried to adjust it a bit and there was instantly a noticeable difference, so I'm guessing that's working.

Could there be some cause for MAF error other that the sensor itself?

Thanks a million!

stedee

iTrader: (4)

i have heard of maf wiring problems , if you wiggled the wires before and something was happening i would suspect that. btw v3/4 mafs are pretty reliable

tikkis

Thanks mate! I think I'll stop by the garage tomorrow and measure the wiring.

tikkis

Definetely something wrong with the wiring. I measured somewhere around 5.5 Volts from ECU ignition on and engine off. Went to wiggle the MAF wires a bit and then measured around 8.5 V. Tried with the old MAF and result was around 9 V. Turned engine on and the voltage rised to about 10.2. I read somewhere that it SHOULD be like 0 - 0.3 ignition on and about 1 V engine running.

Need to be doing some re-wiring then..

tikkis

Re-wired the MAF signal cable, worked instantly like a charm.

Cheers!