Throttle Body: Description and Operation

Throttle Body:

PURPOSE
The throttle body provides control of engine airflow except at idle. The idle airflow is controlled by an idle air control valve.

OPERATION
A 4-bar linkage and cable is used to rotate the throttle shaft from idle to Wide Open Throttle (WOT) on manual transaxle applications. A cam/cable linkage is used on automatic transmssion applications. At all throttle positions, the Throttle Position (TP) sensor produces an electrical signal which is used as an input to the powertrain control module. The WOT plate position is obtained when the lever contacts the body casting. The idle air set or trim screws must not be tampered with. The plate position at idle is set by the lever contacting a throttle return control screw. The head of the screw is removed to make the idle plate set permanently.

CONSTRUCTION
A sealant is applied to the downstream side of the throttle body plate and bore, to reduce plate-to-bore leakage, and the sealant should not be removed by cleaning.