runs, but wont idle
Thread Starter
Junior Member
Joined: May 2010
Posts: 34
Likes: 0
From: Lexington, KY
Car: 1992 formula firebird
Engine: 355 TPI
Transmission: currently a T-5, eventually a T-56
Axle/Gears: 3:42
runs, but wont idle
Hey all, I recently built the engine and got it installed in my 92 firebird, the engine runs good, problem is it wont idle. I installed a new IAC valve when I build the engine? Anybody have any clue what I can do to get this thing to idle?
Thread Starter
Junior Member
Joined: May 2010
Posts: 34
Likes: 0
From: Lexington, KY
Car: 1992 formula firebird
Engine: 355 TPI
Transmission: currently a T-5, eventually a T-56
Axle/Gears: 3:42
Re: runs, but wont idle
Is this one of those stupid questions that I am already supposed to know the answer too know or something??????
Last edited by busterbrown; Nov 7, 2010 at 04:49 PM.
Member
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Joined: May 2010
Posts: 306
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From: Elm City, NC
Car: 87 IROC Z
Engine: 5.7
Transmission: 700R4
Axle/Gears: 3.27
Re: runs, but wont idle
Does it just die when you start it or does it run and idle down? Give us a little more info on what is happening
Thread Starter
Junior Member
Joined: May 2010
Posts: 34
Likes: 0
From: Lexington, KY
Car: 1992 formula firebird
Engine: 355 TPI
Transmission: currently a T-5, eventually a T-56
Axle/Gears: 3:42
Re: runs, but wont idle
It just dies. If I keep pedal to it it will stay running, but as soon as I let off the pedal it will die.
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iTrader: (1)
Joined: May 2010
Posts: 306
Likes: 0
From: Elm City, NC
Car: 87 IROC Z
Engine: 5.7
Transmission: 700R4
Axle/Gears: 3.27
Re: runs, but wont idle
ok. Let's start with the easy stuff. Have you tried adjusting the idle on the throttle body? There is a set screw that is located on the throttle cable assembly on the side of the throttle body. You'll need a torx to adjust and it may have a cap over it. Just punch out the cap and remove. It's not needed.
Thread Starter
Junior Member
Joined: May 2010
Posts: 34
Likes: 0
From: Lexington, KY
Car: 1992 formula firebird
Engine: 355 TPI
Transmission: currently a T-5, eventually a T-56
Axle/Gears: 3:42
Re: runs, but wont idle
yes, I can get it to idle if i adjust throttle body set screw out, but that that isn't the solution to the problem is it? shouldn't the IAC maintain idle?
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Member
Joined: Mar 2009
Posts: 219
Likes: 0
From: Warrior AL
Car: 89 Iroc
Engine: 350/Dart heads/hotcam/TPI
Transmission: T56
Axle/Gears: 3.45 9bolt
Re: runs, but wont idle
Unfortunatley it could be several things. It doesn't really sound like a vacuum leak which I was going to suggest to begin with.
Senior Member
Joined: Dec 2009
Posts: 850
Likes: 8
From: Chilliwack BC
Car: White 1987 IROC-Z
Engine: 305 TPI LB9, 215 HP
Transmission: Borg-Warner T5 NWC
Axle/Gears: Borg-Warner 7.75 with 3.27 ratio
Re: runs, but wont idle
I believe that you answered your own question in this post!!
"I installed a new IAC valve when I build the engine? Anybody have any clue what I can do to get this thing to idle?"
When you installed the new IAC valve, did you follow the procedure correctly?
Search the forum for the correct procedure, or use the FSM, and follow it, this should correct your problem!!
Do not adjust the throttle body set screw, that is used for adjusting the "minimum idle speed only", and it should be set to 450 rpm* (*depending on your engine, and trans)!!
All the above is based on not knowing anything else that you did during your build...........so, it wouldn't hurt to try this!!
Last edited by 87IROC-DAN61; Nov 25, 2010 at 06:21 PM.
Re: runs, but wont idle
First make sure you have no vacuum leaks.
THen go through the throttle body and put duct tape over the IAC holes to prevent air from getting sucked in there.
Disconnect the IAC plug from the IAC.
THEN set the minumum idle.
Reconnect the IAC, remove the tape from the throttle body.
Give it some time to re adjust itself and it will be fine.
If this doesn't do it, you will have to look elsewhere.
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