IAC idle issues
Thread Starter
Joined: Jan 2010
Posts: 1,642
Likes: 19
From: Jacksonville, Fl
IAC idle issues What kinds of things could cause occasional idle air issues?
The Problem: occasionally when letting off the clutch from a light throttle application the engine stalls or comes close to stalling. Has been tuned recently with a H/C/I install.
The diagnosis: myself and the tuner have been working on it, when the stall happens nothing shows why it should be happening. The Idle Air Valve is showing an open status that is being commanded so we thought it might be the valve itself. Well a replacement valve has arrived and although the symptoms are less frequent it still happens randomly.
If the valve, vacuum, and tune have been ruled out, what else could be there culprit? fault MAP sensor?
The whole thing is weird, it's starts right up and idles fine. The IAC follows perfectly from WOT applications, it's only the light throttle applications and doesn't happen all the time.
The Problem: occasionally when letting off the clutch from a light throttle application the engine stalls or comes close to stalling. Has been tuned recently with a H/C/I install.
The diagnosis: myself and the tuner have been working on it, when the stall happens nothing shows why it should be happening. The Idle Air Valve is showing an open status that is being commanded so we thought it might be the valve itself. Well a replacement valve has arrived and although the symptoms are less frequent it still happens randomly.
If the valve, vacuum, and tune have been ruled out, what else could be there culprit? fault MAP sensor?
The whole thing is weird, it's starts right up and idles fine. The IAC follows perfectly from WOT applications, it's only the light throttle applications and doesn't happen all the time.
Thread Starter
Joined: Jan 2010
Posts: 1,642
Likes: 19
From: Jacksonville, Fl
It's a whole new intake tract. 85mm Delphi maf, 92mm Holley tb, dorman ls2. As for the values I can't say I'm not a car computer kind of guy.
Last edited by jaxcam02; Apr 14, 2018 at 01:36 PM.
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Thread Starter
Joined: Jan 2010
Posts: 1,642
Likes: 19
From: Jacksonville, Fl
Looking back on this. DO NOT BUY a throttle body that will not accept an OEM GM or Ac Delco IAC. I had my throttle body machined to accept an OEM IAC and that fixed everything. The Holley IAC is a plastic piece of ****.
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I don't even like the stock LS1 IAC the Holley 95mm and 105mm need. I've found that you can use Autozone AC107 to replace it along with it costing $40 with a lifetime warranty. We have put about 40 into service and haven't heard of one death yet.
