Car wont idle
Thread Starter
Junior Member
Joined: May 2009
Posts: 10
Likes: 0
From: Woodbridge, VA
Car: '89 IROC-Z
Engine: 305 TPI
Transmission: WC T5
Car wont idle
Hey there. I have an 89 Iroc with an LB9 TPI. She wont idle, I have to keep the RPM's up for the engine to stay running, I also have to give her some gas to get it started, before I did not. This just started this morning, and the past two days I have noticed a whistle behind the driver seat that will grow higher in pitch as the RPM's go up. My SES light does come on, however it has since i got the car 6 months ago.I ran the code a long time ago but cant remember what it was, I believe it had to do with the burn off sensor in my MAF. Any input will be greatly appreciated.
Thread Starter
Junior Member
Joined: May 2009
Posts: 10
Likes: 0
From: Woodbridge, VA
Car: '89 IROC-Z
Engine: 305 TPI
Transmission: WC T5
Re: Car wont idle
Update. I went out and put another MAF on that I had lying around, and she runs like a champ, at least for about 5 minutes. I would like to still figure out what was wrong. Hope this helps.
Supreme Member
Joined: Mar 2008
Posts: 1,549
Likes: 1
From: CT
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: Car wont idle
First off we really need to know what codes the ECM is throwing. Second off it might be your idle air control valve or carbon build up in the TB. If no codes show anything interesting to your problem try cleaning the TB ports out and replacing the IAC valve.
Senior Member
Joined: Sep 2009
Posts: 354
Likes: 1
From: Manchester,PA
Car: 86 Firebird SE
Engine: 2.8L
Re: Car wont idle
Didn't GM get rid of the burnoff relay after 85? Anyway, i would do what the last guy said and clean out your IAC valve and ports as well as the throttle body butterfly. Lastly and most important see what code is set in the ECM. This will tell you exactly where to start looking for your problem.
Junior Member
Joined: May 2009
Posts: 56
Likes: 0
From: Westminster, MD
Car: 1986 IROC-Z
Engine: 8100 Vortec (496ci)
Transmission: 4L80E (4spd auto)
Axle/Gears: 9" 40 Spline Detriot Locker 4.90
Re: Car wont idle
will it run and idle fine with just disconnecting the maf sensor?
Supreme Member
Joined: Mar 2008
Posts: 1,549
Likes: 1
From: CT
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: Car wont idle
No not really. The idea is this with the MAF sensor dissconnected the ECM recognises this and just start running off "guesses" as to what it expects there to be for a signal instead of actual data. Now if you had a bad MAF sensor that was sending a BS signal back to the ECM the car would run better by running off of its guesses than the false reading. So it wont rund good but it may run better.
Senior Member
Joined: Sep 2009
Posts: 354
Likes: 1
From: Manchester,PA
Car: 86 Firebird SE
Engine: 2.8L
Re: Car wont idle
There is a way to check for a faulty MAF. Start the engine and let it settle and idle, then with the handle of a screwdriver tap on the MAF housing(dont beat the crap out of it!) if the rpm changes or the idle stumbles, its most likely a defective MAF.
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