IAC valve recommendations?
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,238
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From: walled lake MI
IAC valve recommendations?
after changing the intake manifold gaskets on my 92 i now have a high idle(1200RPM on cluster, i can hear it is high too). i'm going to check out the TPS voltage and reset the IAC later today, but if that doesn't work i'm planning to swap the IAC valve.
the car's always had a slightly high idle (900-1000) even before the gasket change, so i'm hoping the +200 RPM increased idle is due to a cleaned out throttle body.
which finally brings me to my question: has any one of you used the Autozone (Wells) TPS and/or IAC valve?
the car's always had a slightly high idle (900-1000) even before the gasket change, so i'm hoping the +200 RPM increased idle is due to a cleaned out throttle body.
which finally brings me to my question: has any one of you used the Autozone (Wells) TPS and/or IAC valve?
Last edited by tempest; Sep 7, 2004 at 12:29 PM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
You might check manifold vacuum for any indication of an air leak.
When changing the IAC valve, be sure to clean the bore under the TB and reset base idle to 450rpm.
Your TPS isn't adjustable; so, if the voltage changes smoothly from idle to WOT it is ok.
When changing the IAC valve, be sure to clean the bore under the TB and reset base idle to 450rpm.
Your TPS isn't adjustable; so, if the voltage changes smoothly from idle to WOT it is ok.
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
65Z01, thanks for the quick reply. i have some follow-up questions:
- what should vacuum be at idle?
- how do i reset my base idle? is the "step on pedal, ignition on, wait 10 seconds, shut off" method enough? will removing battery for 15 minutes acheive the same thing?
i just tried both the pedal reset method and removing battery power to reset - it did lower idle speeds a little, but it is still over 1000RPM at normal operating temps.
i'll follow your suggestions and keep at it.
- what should vacuum be at idle?
- how do i reset my base idle? is the "step on pedal, ignition on, wait 10 seconds, shut off" method enough? will removing battery for 15 minutes acheive the same thing?
i just tried both the pedal reset method and removing battery power to reset - it did lower idle speeds a little, but it is still over 1000RPM at normal operating temps.
i'll follow your suggestions and keep at it.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by 65Z01
You might check manifold vacuum for any indication of an air leak.
When changing the IAC valve, be sure to clean the bore under the TB and reset base idle to 450rpm.
Your TPS isn't adjustable; so, if the voltage changes smoothly from idle to WOT it is ok.
When changing the IAC valve, be sure to clean the bore under the TB and reset base idle to 450rpm.
Your TPS isn't adjustable; so, if the voltage changes smoothly from idle to WOT it is ok.
Jake
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by tempest
which finally brings me to my question: has any one of you used the Autozone (Wells) TPS and/or IAC valve?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
I've used a NAPA IAC and TPS on my other GM products without any problems. Reset the IAC and hookup a scanner. You want to see what the ECM is targeting for RPM and compare it with actual (which should be no more than 100 rpm's greater in Park or Neutral; 50 rpms in Drive). Check IAC counts. They should be about 12 with the a/c off. As far as I know, there isn't any minimum air or idle for your year. If you want to check vacuum, it should be about 14 to 17 and steady. Follow the vacuum line diagram in the engine compartment and make sure all the lines are intact
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
The IAC doesn't have an "adjustment" for installation. Just an installation position to prevent damage. The ignition on, for 10 seconds, etc, is the calibration or adjustment. Based on the most recent project, I'd bet money you've left a vacuum leak somewhere.
RACE ON!!!
RACE ON!!!
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,238
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From: walled lake MI
well, looks like you're right CFI.
i tested manifold vacuum while cranking, and plugged holes in the manifold one at a time. eventually i got to the EGR valve. plugging that hole yielded a much slower loss of vacuum.
i cranked on the EGR valve bolts a bit more and now idle is down closer to 1000 RPM. (how the hell do you "feel" the right torque for those bolts anyway??? can't get a torque wrench on em.) so my problem is either - incorrect torque on EGR valve bolts, crappy paper EGR valve gasket (it is new), or a bad valve itself, or a combination.
i'm fairly certain it's the valve - when i vacuum tested with the bolts cranked down, i can hear a sucking sound near the passenger side AIR pipe when i stopped cranking.
later this week just for kicks i will try and replace the paper gasket and use RTV red instead and see the effects. if that doesn't work i guess i'll have to shell out some $$ for a new valve.
yet again, thank you all for your help.
i tested manifold vacuum while cranking, and plugged holes in the manifold one at a time. eventually i got to the EGR valve. plugging that hole yielded a much slower loss of vacuum.
i cranked on the EGR valve bolts a bit more and now idle is down closer to 1000 RPM. (how the hell do you "feel" the right torque for those bolts anyway??? can't get a torque wrench on em.) so my problem is either - incorrect torque on EGR valve bolts, crappy paper EGR valve gasket (it is new), or a bad valve itself, or a combination.
i'm fairly certain it's the valve - when i vacuum tested with the bolts cranked down, i can hear a sucking sound near the passenger side AIR pipe when i stopped cranking.
later this week just for kicks i will try and replace the paper gasket and use RTV red instead and see the effects. if that doesn't work i guess i'll have to shell out some $$ for a new valve.
yet again, thank you all for your help.
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