Idle Air Control (IAC) System

IAC system consists of electrically controlled motor (actuator) which positions a pintle in the air by-pass channel around throttle valve. See Figure. IAC is held in by screws on the model 700 TBI. ECM calculates desired position of IAC valve based upon battery voltage, coolant temperature, engine load and engine speed, to control idle speed and prevent stalls due to engine load changes.

There are several different conical IAC pintle designs used. Ensure that correct design and type is used if IAC is replaced.