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
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 permanent. The idle air control or trim screws must not be tampered with. The wide open throttle plate position is obtained when the lever contacts the body casting. At all throttle positions, the throttle position sensor produces an electrical signal which is used as an input to the powertrain control module.

CONSTRUCTION
A cam/cable linkage is used to rotate the throttle shaft from idle to wide-open-throttle position. 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.