Throttle Body: Description and Operation

Throttle Body Assembly:

The throttle body assembly controls airflow to the engine through a double butterfly-type valve. The throttle position is controlled by multiple-link, progressive opening, throttle linkage. The body is a single piece die casting made of aluminum. It has a dual bore with an air bypass channel around the throttle plate. This bypass channel controls both cold and warm engine idle airflow control as regulated by an air bypass valve assembly mounted directly to the throttle body. The valve assembly is an electro-mechanical device controlled by the EEC-IV computer. It incorporates a linear actuator which positions a variable area metering valve. The idle speed screw engages the primary throttle lever for all transmissions.

Throttle Body Assembly:

Other features of the air throttle body assembly include:
a. A pre-set stop to locate the WOT position.
b. A throttle body mounted throttle position sensor.
c. Canister purge ports (2) for evaporative emission control.