Dave91

Anyone have a guide or the steps to replacing the IAC on a '91 L98? I have observed it once so have a pretty good idea but I would like to have some instructions or something to follow to make sure I get all the correct bolts.

I have the Haynes manual but haven't been able to find anything in there to get me going in the right direction and a google search of the web hasn't helped much, either.


Thanks.

65Z01

With ignition Off disconnect the harness from the IAC connector and remove the IAC.

Clean the bore in the IAC housing under the TB with TB cleaner. You should also clean the TB bore & blades at this time.

Install the IAC, per directions supplied with the unit and connect the wiring harness.

Start the engine and check idle. If idle speed doesn't settle to 600-700rpm in Park use the method on my site to set base idle.

Square

If you can remove your IAC with the throttle body on, then the above post is way easier than what I originally had typed!

mikey whipreck

I was able to get the IAC off on my '85 l98 by just loosening the TB. I unbolted it, and lifted it up to where I could get a wrench on the IAC. Just be very careful with the gaskets, and the coolant hose...

SunCr

Remove and replace. Then slightly depress the pedal and start. Run 10 seconds; off 5 seconds, restart.

CFI-EFI

And don't forget to retract the pintle, as per the factory (Helms) manual, before you reinstall it. You COULD damage the pintle, pintle seat, the IAC motor itself, or all the above.

EACE ON!!!

dgoodhue

I would get new gaskets, lower TB and IAC gasket while you at it. Also, pull apart and really clean the IAC passage below the TB.

Wayne88

Thats what I did, also did the TB bypass.

Blue88

Hey 65Z01. I used the tech tips on your site when I bought my 88 two years ago and it saved me alot of time and money. Thanks