Auxiliary Air Valve (Idle Speed): Description and Operation

(IAC Valve)- Air Regulator:

PURPOSE
Provides cold engine fast idle.

OPERATION
When engine coolant temperature is low, the air by-pass port opens. This allows air to by-pass the throttle plate, increasing idle speed. As the coolant temperature increases, the wax element expands, pushing the valve to the closed position. This lowers engine speed.

CONSTRUCTION
Wax, piston and spring are built into the valve. It has an air inlet port and an exhaust port.