IAC(Idle Air Control) valve Tuning

Gday all,

Im unaware if there is other names for it but the IAC has Steps when I look at tables and scales for it I’m just wondering what do all these do if I increase or decrease the steps that get added in any given condition.

will this change how the revs hang when changing gear will less steps make it drop back to idle faster, will too little steps cause it to stall when dropping back to idle just some more info on how tuning the IAC steps works would be appreciated

unless someone can link me to some topics or stuff that already discussed this and I just missed it would be great thx

Your IAC is probably a stepper-motor type - it adjusts how much air the engine can get when the throttle is closed. These would normally be reset (ie, stepped all the way to full open or full closed) at either startup or shutdown, then stepped back to a known position for starting, adjusted during idling to maintain the target idle speed, and set to a specific position when you exit the idle mode by pressing the throttle. This last setting appears to be what you are describing.

Search for Idle Control in the webinars, but I think this one might be useful to you, even though it's specifically about an engine with Electronic Throttle Control vs IAC:

https://www.hpacademy.com/previous-webinars/217-idle-tuning-hp-tuners-gmhp-tuners/

Scott,

Stepper motors move in physical steps so you're setting the step count instead of a duty cycle on a solenoid style IAC, but the process and impact is essentially the same.

Just keep in mind some control strategies and stepper motors operate in a fashion that higher values = less not more airflow, but do a quick test adjusting it and then you'll know which direction your system operates and can go from there.

Awesome info thx heaps gonna have a play around tonight Mike

and I’ll have a watch of that when I get the chance thx Dave