Idle Speed/Throttle Actuator - Electronic: Description and Operation

Idle Air Bypass Valve Assembly:

The Idle Air Bypass Valve assembly,located on the left side of the upper intake manifold assembly, is an EEC controlled solenoid valve used to regulate idle speed by metering the amount of air allowed to bypass the throttle valve. The valve permits EEC adjustments to idle speed for these purposes:

1. Cold engine fast idle.
2. No touch start.
3. Over temperature idle boost.
4. Idle speed correction for engine load.

The valve is a two piece assembly consisting of an electrical solenoid and a mechanical valve body. Idle speed control is accomplished by a duty signal from the ECA computer to the solenoid which in turn regulates the valve body opening and amount of bypass air.