Idle Speed/Throttle Actuator - Mechanical: Description and Operation

The Throttle Opener, located on the side of the throttle valve, performs much the same function as a dashpot. The Throttle Opener reduces Hydrocarbons (HC) and Carbon Monoxide emissions by returning the throttle plate slowly to the idle position during deceleration. This allows the air fuel mixture to burn more completely than if the throttle were closed abruptly.

The Throttle Opener consists of a spring loaded diaphragm that extends when the throttle is opened. When the throttle valve is released and comes in contact with the actuator pin, manifold vacuum pulls the diaphragm and plunger back, returning the throttle valve slowly to its idle position. The Throttle Opener plunger is adjustable. Refer to ADJUSTMENT PROCEDURES for proper procedure.