by Douglas Black

Created on: October 01, 2008

The automobile engine is a perfect balance of science and mechanical engineering. Each part is carefully designed to interact with one another in a perfect synchronous harmony to produce a means of transportation. One very small but vital component found in this mass orchestra of mechanics is the Idle Air Control valve, or better known to mechanics as the IAC.

Basically the IAC was designed to control the engine idle speed, and the dampers also known as the dashpot functions. The valve is used to control the amount of air that can enter the motor during idling. After you remove your foot from the accelerator and the motor is no longer being fed the mixture of fuel and air through the injectors your motor goes into an idle mode. During idling the throttle plate goes into place, which is why you need an IAC valve control to allow air to bypass the throttle plate. Without an IAC valve the engine would be starved the necessary ingredients to sustain combustion, resulting the dreadful stall.

So how do I know when the IAC is faulty and needs to be replaced?

Actually the great yin and yang of modern day mechanics is the onboard computer that maintains all the vital controls. To older mechanics that much prefer carburetors instead of fuel injection, the computer might not be our best friend. But to the untrained automobile owner it can ensure you don't get stuck on the side of the highway.

The IAC has sensors that are used to relay information to the main computer CPU, which determines if every component is doing the right thing. If any component like the IAC begins to produce substandard readouts then the most feared "check engine" light found on the dashboard console lights up like a Christmas tree.

Once the IAC stop properly regulating air control it sends a message immediately to the processor, which attempts to compensate if possible. If the compensation is not able to resolve the issue it sends another message to turn on the switch for the check engine light and soon if not already you may start experiencing problems related to the IAC.

Stalling, accelerating and even slowing down can all show some changes when the IAC is not functioning properly? In some cases the motor will not even be able to stay running after you turn it over, and eventually all you will get is the chugging of the starter motor.

How to clean the IAC valve:

If you are comfortable with trying new things and have some mechanical aptitude then you might want to try cleaning your IAC valves before going

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