IAC, Idle Air Control, is a little valve that controls a vacuum leak on fuel injected vehicles. In a carbureted application the throttle blades allow just enough air for the car to idle to pass through the “closed” throttle blades. In a typical single blade throttle body the amount of air that can go around the blade isn’t enough to maintain a fixed idle speed when loads change. The IAC opens and closes to control the airflow in order to maintain a target idle speed.
Setting your IAC is the difference between a great running ride and one that hunts for idle every time you turn on the AC or crank up the stereo. In the video below, Holley shows you how to do just that properly with your Terminator X.
Video Description:
Having high or rough idle on your Holley Terminator X drive-by-wire setup? Here’s how to quickly set up your idle airflow correctly.
On DBW systems, there’s no physical IAC valve—the throttle blade controls idle through the pedal vs. throttle table. With the engine fully warmed up, adjust the 0% pedal cell until your IAC position is under 10% at idle.
IAC above 10–15%? Raise the value. IAC at 0% but idle too high? Lower the value.
You can make this adjustment using the 3.5” handheld, Holley app (Bluetooth), or Terminator X laptop software.
Dial this in for a smooth, steady idle and proper DBW performance.
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