Is the IAC my problem? Inconsistent idle @ startup

Reply Subscribe

Thread Tools

Search this Thread

Jun 5, 2009 | 06:56 AM

bigburb

Thread Starter

On The Tree

iTrader: (3)

Joined: May 2004

Posts: 119

Likes: 0

Is the IAC my problem? Inconsistent idle @ startup

When ever I first start up my car its seeks a little bit to find the right idle. For example it starts right up but then comes back down to 400 RPM, then bounces around 800-1000 RPM a couple of times before it settles down. Also when I try to start it with the AC is on it has a real hard time staying running and sometimes dies. If its been running for more than 60 seconds there's no problem, its just on start up. My tuner said this was the IAC valve getting slow, does that sound right? Just wanna know for sure before I drop $100 on a new one. Thanks.

BTW I have a GM ASA Cam, full exhaust, ported and expoxied TB, and custom dyno tune, if that helps any.

Last edited by bigburb; Jun 5, 2009 at 07:23 AM. Reason: Added engine details.

Jun 5, 2009 | 08:19 AM

bigburb

Thread Starter

On The Tree

iTrader: (3)

Joined: May 2004

Posts: 119

Likes: 0

Did some searching, could it be the epoxy mod? I'd rather have a consistent idle and be able to start it with the AC on then have 5 extra HP at 6000 RPM. should I remove it?

Jun 5, 2009 | 08:20 AM

69LT1Bird

11 Second Club

iTrader: (1)

Joined: Sep 2007

Posts: 2,310

Likes: 6

From: Lapeer, MI

Have your "tuner" monitor the IAC data to see what it is doing. Maybe he didn't tune the closed loop/cold start areas?

Jun 5, 2009 | 08:27 AM

bigburb

Thread Starter

On The Tree

iTrader: (3)

Joined: May 2004

Posts: 119

Likes: 0

Quote:

Originally Posted by 69LT1Bird

Have your "tuner" monitor the IAC data to see what it is doing. Maybe he didn't tune the closed loop/cold start areas?

I've had it tuned by two different guys, it got better with the second tune but still not just right. On the first tune I couldn't even start it with the AC, and I had to let it find its idle before taking off. On the second tune I can take off when I start it and it'll start with the AC on but it doesn't like it much.

The second guy who tuned it seemed like he knew his stuff (he tuned for 3 performance shops including his own)