IAC-How do I know its good?
Thread Starter
Instructor
Joined: Apr 2004
Posts: 217
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From: Winnipeg MB
IAC-How do I know its good?
Hi
I was having a few issues with my 85. One of them was I couldnt get the rpm below 1100. I just purchased the car so I dont know the history.
Anyway, I set the idle speed and tps according to the method in this forum. I disconnected the IAC to start and set the idle to 450 rpm. I set the tps to .54V at idle. I started the car and since it was at operating temperature, it came down to a nice idle at 620rpm.
This morning I fired it up again cold. It wouldnt come down below 1100 rpm. I removed the throttle body and IAC and cleaned them, but how do I know the IAC is good? Maybe some other sensor is telling it to open? Why did it work good when I reset things last night?
Also, what is the proper procedure for cleaning the IAC? Is there any adjstments?
All help apreciated!!
Thanks
I was having a few issues with my 85. One of them was I couldnt get the rpm below 1100. I just purchased the car so I dont know the history.
Anyway, I set the idle speed and tps according to the method in this forum. I disconnected the IAC to start and set the idle to 450 rpm. I set the tps to .54V at idle. I started the car and since it was at operating temperature, it came down to a nice idle at 620rpm.
This morning I fired it up again cold. It wouldnt come down below 1100 rpm. I removed the throttle body and IAC and cleaned them, but how do I know the IAC is good? Maybe some other sensor is telling it to open? Why did it work good when I reset things last night?
Also, what is the proper procedure for cleaning the IAC? Is there any adjstments?
All help apreciated!!
Thanks
Team Owner
Joined: Oct 2004
Posts: 35,065
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
As far as I know, you have to disassemble and clean or replace it. There's no way to tell for shure without looking at it. By the time you have it apart enough to look at it, may as well just replace it.
-Also, check your injectors. They should read 16-17 ohms.
Hope it's the IAC. Cheeper and easier.
-Also, check your injectors. They should read 16-17 ohms.
Hope it's the IAC. Cheeper and easier.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Remove IAC, push pintle all the way in by hand, measure the distance, then reinstall it.
Put car in diagnostic mode and turn key on 30 seconds. Feel the IAC, it should be vibrating. Turn car off, remove IAC. See if it extended
Put car in diagnostic mode and turn key on 30 seconds. Feel the IAC, it should be vibrating. Turn car off, remove IAC. See if it extended
Team Owner
Joined: Oct 2004
Posts: 35,065
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Again, if I'm going to do all that, I'll throw n a new part.
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Thread Starter
Instructor
Joined: Apr 2004
Posts: 217
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From: Winnipeg MB
I know it vibrates because I had it diagnostic mode and couldnt figure out twhat the sound was. What does an IAC sell for roughly? I cant for the life of me push in the pintle by hand. Seems like I am going to bend the rod!
How does it work? Extended blocks off air passage? Retracted opens? Or opposite?
Thanx
How does it work? Extended blocks off air passage? Retracted opens? Or opposite?
Thanx
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I know it vibrates because I had it diagnostic mode and couldnt figure out twhat the sound was. What does an IAC sell for roughly? I cant for the life of me push in the pintle by hand. Seems like I am going to bend the rod!
How does it work? Extended blocks off air passage? Retracted opens? Or opposite?
Thanx
How does it work? Extended blocks off air passage? Retracted opens? Or opposite?
Thanx
You can get an AC Delco one on line for about $40.
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Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
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From: Orlando FL
St. Jude Donor '08-'09
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From: Summerland B.C. Canada
Le Mans Master
Joined: Feb 2000
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From: Kempner Texas
I know it vibrates because I had it diagnostic mode and couldnt figure out twhat the sound was. What does an IAC sell for roughly? I cant for the life of me push in the pintle by hand. Seems like I am going to bend the rod!
How does it work? Extended blocks off air passage? Retracted opens? Or opposite?
Thanx
How does it work? Extended blocks off air passage? Retracted opens? Or opposite?
Thanx
As you press on the pintel, you wiggle the pintel from side to side. It'll go in gradually.
In operation, as it extends, it closes off the air passage and as it retracts it does the opposite.
Jake
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Instructor
Joined: Apr 2005
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From: San Antonio TX
Others outlined using diagnostic mode to test for full extension. Retraction can be checked by running and stopping and removing the key. Normal starting postion is 160 steps. You can even do this with the IAC removed (and powered). If you try to check extended with it removed you can shoot the pintle.
Safety Car
Joined: Feb 1999
Posts: 3,504
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From: Mexico Beach FL
I don't know about earlier models, but on a '92 you can use a Vetronix Tech-1A scan-tool to command a higher idle rpm -- if the engine responds correctly, you know the IAC is ok.
The Vetronix scan-tools are "bi-directional", they send commmands in addition to reading the data like other scan-tools.
Tom Piper
The Vetronix scan-tools are "bi-directional", they send commmands in addition to reading the data like other scan-tools.
Tom Piper