Throttle Body: Description and Operation

Throttle Body:

Airflow to the engine is controlled by the throttle body through a single butterfly-type valve. The throttle position is controlled by conventional cable/four-bar throttle linkage or cable/single lever throttle linkage. The body is a single-piece die casting made of aluminum. It has a single bore with an idle air bypass channel around the throttle plate. Through this bypass channel flows both cold and warm engine idle airflow as regulated by an Idle Air Bypass (IAB) valve assembly mounted directly to the intake manifold. The valve assembly is an electro-mechanical device controlled by the Electronic Control Assembly (ECA). It incorporates a linear actuator which positions a variable area metering valve.