Air Throttle Body Assembly Operation

The throttle body assembly controls airflow to engine through a single (2.3L, 2.9L and 3.0L engines) or a double (5.0L engine) butterfly valve. Throttle position is controlled by multiple-link, progressive opening throttle linkage or a conventional cable/cam throttle linkage. Throttle body is a single piece die casting made of aluminum. It has a single (2.3L, 2.9L and 3.0L engines) or a dual (5.0L engine) bore with an air by-pass channel around throttle plate.

This by-pass channel controls both cold and warm engine idle airflow control as regulated by an air by-pass valve assembly mounted to air cleaner (2.3L engine), upper intake manifold (2.9L engine) or throttle body (3.0L and 5.0L engines). Valve assembly is an electro- mechanical device controlled by EEC module.

It incorporates a linear actuator which positions a variable area metering valve. It also features a preset stop to locate W.O.T. position, a throttle body mounted throttle position sensor, canister purge ports for evaporative emission control (2.9L and 5.0L engines), an adjustment screw to set throttle plate at minimum idle airflow position (2.3L and 3.0L engines), crankcase ventilation pressure tube (2.9L engine), closed throttle stop-set screw (2.9L engine), provision for EGR valve and sensor mounting (3.0L engine), a built in torsional return spring (3.0L engine) and individual ported vacuum taps for PCV and EVAP control signals (3.0L engine).