IAC question
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Joined: May 2001
Posts: 69
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From: Ida, Michigan, USA
IAC question
I just pulled my throttle body assembly off of my 94 Vette for a good cleaning. It's part of my yearly tune up. The idle was starting to get a little rough. It seemed to hunt a bit once it warmed up. After removing the IAC I saw that it had a lot of carbon build up. My question is, should it move freely with the spring or not. Mine does not move at all. I would expect a bit of resistance from the stepper motor but I have to apply quite a bit of force to push it in. Is this normal? Can the internals be cleaned or do I need a new one? Thanks for any help on this one
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Joined: Mar 2005
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My manual warns against trying to move one that isn't new- it may be damaged by that action. So if you haven't burned that bridge yet, you're fine. The rough idle might be fixed by cleaning or resetting, or may be the start of the end for your IAC. They're about $75.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by ls5454
My manual warns against trying to move one that isn't new- it may be damaged by that action.
RACE ON!!!
Last edited by CFI-EFI; Apr 12, 2005 at 01:41 PM. Reason: Typo.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
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From: Austin Texas
Originally Posted by CFI-EFI
My manual says to move it. The 1994 manual may read differently. The pintle is to be retracted to a length of 1 1/8th" before installation. This is to prevent damage to the valve, the seat or the stepper motor, itself. Sometimes twisting or rocking the shaft, slightly, will help retract the pintle. It does take considerable effort. The shaft and valve should be cleaned. The inside of the IAC motor is off limits, it cannot be cleaned. Submersing it in a cleaning fluid will ruin it. The air passages to and from the IAC should be thoroughly cleaned.
RACE ON!!!
RACE ON!!!
Hopefully you didn't force it too hard and break it. If there is alot of carbon buildup as you indicate on the pintle shaft, it could be sticking and the response may be sluggish, causing a "hunting idle". You can safely clean the pintle and shaft by spraying it liberaly with carb cleaner or TB cleaner; just make sure you hold it with the pintle facing the ground so the cleaner does not get into the stepper motor housing. 
