Throttle Body: Description and Operation

PURPOSE
The throttle body provides control of engine air flow.

OPERATION
- A cam lever and accelerator cable rotates the throttle shaft from idle to Wide Open Throttle (WOT) position.

- The plate position at idle is factory set by the lever contacting a throttle return control screw. The head of the screw is removed to make the idle plate set permanent. DO NOT attempt to adjust idle/minimum plate setting with the throttle return control screw.

- The throttle body airflow is factory set by the idle air adjust needle (trim screw) within the throttle body casting. DO NOT attempt to adjust.

- Throttle body idle airflow provides minimum engine airflow while the Idle Air Control (IAC) valve provides supplemental engine airflow to maintain the desired engine idle speed.

- The WOT plate position which is obtained when the lever contacts the throttle body casting.

- The Throttle Position (TP) which provides an electrical signal which is used as an input to the Powertrain Control Module (PCM).

- The throttle body has a sealant which is applied to the downstream side of the throttle body plate and bore to reduce plate-to-bore leakage. Cleaning may remove sealant. It should NOT be cleaned.