MAF disconnected runs fine MAF connected runs rich...

[bolton94Z]

ok so heres my problem found out why my car was running rich when the MAF is connected as soon as it goes into closed loop my long term BLMs drop like a rock to 112-113 and sometimes lower. Now heres the weird part with the MAF dissconnected when the car goes into closed loop my BLM's stay around 131-130 which is fine, so I thought the MAF was bad got a new sensor same problem, checked wiring its fine. So what hell is going on this is pissing me off after I finally figured out the cause I get a MAF and it does the same thing...any ideas? thanks

[Fastbird]

Been tuned? If yes, talk to tuner. If no, could stand to have one as factory tunes are on the rich side to begin with.

[bolton94Z]

No has not been tuned I just didn't think it would run so rich like that with the minimal mods I have. I'm getting a tune from madz28 Ion. Hopefully that will help. cause i can't understand why it would run better using speed density instead of the maf.

[lt170chevelle]

yeah they do run on the rich side from the factory

[bolton94Z]

its to the point when the MAF is plugged in that it is stumbling from a stop like if i'm at a red light when I go it stumbles cause it runs so rich at idle. blms sometimes go down to 108 witch is as low as it can go i get about 12 MPG. I would say something else is wrong. Cause without the MAF blms are much better runs ALOT smoother and i get about 18-19 MPG city driving...I dunno this is just really wierd especially after I tried a new MAF.

[Fastbird]

Got a spare MAF to try on it?? Could be that something got damaged on your MAF.

[bolton94Z]

Got a spare MAF to try on it?? Could be that something got damaged on your MAF.

yeah used a friends MAF it did the same thing...I guess I'll just keep running with it unplugged cause I don't know what the hell is going on..

[Fastbird]

Are there ANY leaks after the MAF? Elbow is common, TB gaskets, Upper/Lower plate gaskets, intake manifold gaskets, ect. Any kind of unmetered air introduced into the system will cause a lot of issues.

[bidicamaro]

Doesn't the MAF run with the rear O2 sensors as well?

[bolton94Z]

Doesn't the MAF run with the rear O2 sensors as well?

I don't know but my 94 does not have rear 02 sensors.


Are there ANY leaks after the MAF? Elbow is common, TB gaskets, Upper/Lower plate gaskets, intake manifold gaskets, ect. Any kind of unmetered air introduced into the system will cause a lot of issues.


I'll have to take a look at that this weekend I got to much school and work this week. Thanks for the suggestions.

[Z28pr0jekt]

what are the IAC counts doing?

[bolton94Z]

what are the IAC counts doing?



Low 30's at idle 32 is what it usually is and acts normal under accelerating.

[Fastbird]

If you're datalogging, email a couple of logs to me and let me have a look. Doubtful that it's a leak because your IAC would be closing farther than that.

[bidicamaro]

I don't know but my 94 does not have rear 02 sensors.



Oh yeah, I knew that... Mine doesnt either... Sorry about that...