Iroc_87

I have a 89 TPI stock. So my car has been idling rough lately almost to the point where it turns off, but it doesn't. People told me to clean the IAC and I did that but the problem continues. I have an SES light which gives me code 33 and 36, both related to the MAF. Could my car idle rough because of the MAF?

Thanks

kcallais

Yes, yes it very well could idle rough because of the MAF. The MAF meters the air going into the motor, then constantly sends that info to the ECM to adjust fuel mixture. Its a pretty big player in idle operation. Try this.....with the engine running at operating temperature, disconnect the electrical connector from the MAF. If the car keeps running, the MAF is bad. If it shuts off, then more than likely your MAF is fine.

I would also suggest making sure all lines are connected to your throttle body. Theres a small EGR line underneath the TB, the PCV on the passenger side, and a line going to the charcoal canister beneath the PCV port. If all of these are connected fine, (along with the rest of your vacuum system, particularly ALL pcv lines) then try adjusting the idle setscrew to open the TB valve a little. My car is a little uncooperative after I disconnect the battery, and each time I have to reset the idle screw so the TB valve is closed, start the motor, then adjust the screw until I like how it sounds. You may have to do the same with yours.

Iroc_87

Thanks for all the info. I recently swapped to a 350 and my mechanic left the MAF relays unconnected. I'm not sure if I connected them properly. If I didn't could that be causing this problem?

Iroc_87

So I turned on my car and it was idling at like 1600 rpms, I let it warm up and I disconnected the MAF wire and the idle dropped to 900 rpms. Does this mean the MAF is bad?

king1960

Engine shoud die when maf is un plugged.

Iroc_87

So does this mean I definitely need a new MAF?

doc

Do you know anyone with an 87, 88, or 89 305 or 350 TPI ? If yes, borrow it for 2 minutes.

Also, if you are serious about this car, buy a scanner so that you can "see" what the ECM is "seeing". Recently, my MAF went bad, but I thought that it was bad fuel injectors. The MAF was always reporting high flow numbers even though the car was idling (trying to idle) in the garage.

Iroc_87

That's what I was thinking. Too bad I don't know anyone around here with a MAF third gen.