IAC valve: what do I do to test the circuit?
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Joined: Jul 2009
Posts: 752
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Car: 1991 Z28
Engine: 5.7 TPI
Transmission: 700R4
IAC valve: what do I do to test the circuit?
I developed an erratic idle and hard start, so I replaced my IAC valve. The car seems to start better and the idle isn't all over the place, but it seems to jump up to 1500 pretty quick and wants to stay there. I have checked but can not seem to find any vacuum leaks...
I have heard I need to set the Minimum Air, but why would I need to do that if I never tinkered with it in the first place? Perhaps my electrical connection is at fault? How do I test the pigtail?
I have heard I need to set the Minimum Air, but why would I need to do that if I never tinkered with it in the first place? Perhaps my electrical connection is at fault? How do I test the pigtail?
Joined: Dec 2004
Posts: 16,811
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: IAC valve: what do I do to test the circuit?
You can check it with a iac noid, sounds like the iac is sticking or the motor is shot.
Member
Joined: Jan 2009
Posts: 292
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From: North Carolina
Car: Pontiac 89 GTA
Engine: 350 TPI 5.7L V8
Re: IAC valve: what do I do to test the circuit?
Is your dip stick tube in the hole?
I have a 89 GTA and the tube felt of And since then my car will Idle very hi
I have a 89 GTA and the tube felt of And since then my car will Idle very hi
Joined: Dec 2004
Posts: 16,811
Likes: 1,008
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: IAC valve: what do I do to test the circuit?
Have you checked for vacuum leaks ?
Thread Starter
Senior Member
Joined: Jul 2009
Posts: 752
Likes: 1
Car: 1991 Z28
Engine: 5.7 TPI
Transmission: 700R4
Re: IAC valve: what do I do to test the circuit?
That was weird- I checked my dipstick again and it was loose. Put it back in place and the think wouldn't idle at all without me giving it gas. Drove it for a while and the idle climbed back up to 1500 again. Started it again and it idled beautifully for a minute then back up to 1500!
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Joined: Sep 2009
Posts: 598
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From: PHOENIX/ TOLLESON ARIZONA
Car: 90 IROC 5.7 1LE CLONE 89 GTA 88IROC
Engine: 5.7TPI / 5.7TPI/ 5.7TPI/ 4.3 CMFI
Transmission: 700R4 UPGRADED 700R4STOCK700R4STOCK
Axle/Gears: 3.23 10 BOLT 3.27 9 BOLT 2.77 9BOLT
Re: IAC valve: what do I do to test the circuit?
That was weird- I checked my dipstick again and it was loose. Put it back in place and the think wouldn't idle at all without me giving it gas. Drove it for a while and the idle climbed back up to 1500 again. Started it again and it idled beautifully for a minute then back up to 1500!
OR ITS GETTING EXTRA AIR FROM SOMEWHERE ?
MY PROBLEM IS THE ENG FIRES AND DIES IMMEDIATELY AFTER START. IT WILL IDLE IF I OPEN THE THROTTLE PLATE SLIGHTLY. I SUSPECT THE IAC IS STICKING CLOSD. ILL POST MORE WHEN I RUN MORE TEST / CLEAN IT ETC...
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