We're pretty sure that the IAC valve on my car is screwed up. I will have a new one waiting at the house when I get home. My question is, since my current one doesn't work, how should I install the new one?

Should I just put it in, or should I try to open it up or close it? Is there a good happy medium?

 

I just replaced mine on my '93. There are some pretty good instructions posted under Tech Tips. In short, Replace the IAC, depress the gas peddle slightly and start the engine, run 5 seconds, shut off for 10 seconds, and then re-start as normal. This is supose to reset the IAC with the computer.

Good luck!

 

Aside from what Bob said,many times the IAC itself will have a small instruction sheet included for the distance it should be set.Im not sure,but I think some come already preset and you have to remove the rubber cap or ring only and install.

If you have a shop manual,see what the specs say for measurement should be for installation.
Btw,with your old IAC,was the pintel(sp?) frozen and not able to push in and out by hand?
Just curious.
:)

 

You can move it, but it's really stiff. I'm about 99% confident it's broken now. :)

I took it out and it pulled out very easily, I put it back and the car wouldn't idle at all without my foot on the throttle, and it never adjusted. I pulled the IAC back out and pushed it in a little, that was extremely stiff. I just decided to wait till today and get the new one.

 

This is from the 1994 GM Factory Serive Manual, Book 2:

IDLE AIR CONTROL (IAC) VALVE

Remove or Disconnect
1. Electrical connector from IAC valve.
2. IAC valve assembly attaching screws.
3. IAC valve assembly.

NOTICE: On IAC valves that have been in service: Do not push or pull on the IAC valve pintle. The force required to move the pintle may damage the threads on the worm drive. Also, do not soak IAC valve in any liquid cleaner or solvent, as damage may result.

Clean and Inspect
„h Clean IAC valve and O-ring sealing surface, pintle, valve seat and air passage.
ƒ{ The IAC valve may be cleaned using GM cleaner 1052626 or GM X-66A. Use a shop towel or parts brush to remove heavy deposits.
ƒ{ Shiny spots on the pintle or seat are normal, and do not indicate misalignment or a bent pintle shaft.
ƒ{ If air passage has heavy deposits, remove throttle body for complete cleaning.
„h Inspect IAC valve and O-ring for cuts, cracks, or distortion. Replace if damaged.

Important!
„h If installing a new IAC valve, be sure to replace with an identical part. IAC valve pintle shape and diameter are designed for the specific application.

Measure (If installing a New IAC Valve)
„h Distance between tip of IAC valve pintle and mounting surface.
ƒ{ If more than 28 mm, use finger pressure to slowly retract the pintle. The force required to retract the pintle of a new valve will not cause damage to the valve.

Install or Connect
1. Lubricate IAC valve O-ring with clean engine oil.
2. IAC valve assembly.
3. IAC valve attaching screws.

Tighten
„h IAC valve attaching screws to 3 N-m (27 lb. in.).

4. Electrical connector to IAC valve
5. Reset IAC valve pintle position:

A. Depress accelerator pedal slightly.
B. Start engine and release accelerator pedal, run engine for 5 seconds.
C. Turn ignition ¡§OFF¡¨ for 10 seconds.
D. Restart engine and check for proper idle operation.

 

Well I got home and installed the new IAC. So far so good. Now I just have one plug wire that need replacing and a popping somewhere in the chassis that needs to be addressed and I'll be ready to go again.

What does everything always seem to break at once? It's so much more frustrating to try and diagnose 30 problems at once.

Thanks all for the help :cheers: