Air Induction
The air induction system conditions and measures the amount of air entering the engine. A standard air temperature system heats incoming air and maintains it at a chosen temperature. A temperature sensing valve, check valve, and vacuum motor control the heating functions.
A special duct on the air cleaner is used to swirl the incoming air. A special sensor then determines the quantity of air entering, and feeds a control signal to the computer. When the engine is cranking, not enough air flows for the sensor to work, so air flow is estimated by the computer.
The final component in the air induction system is the throttle body. It is located on top of the intake manifold and contains the throttle blades, several vacuum ports, and the Automatic Idle Speed (AIS) motor. In addition, a throttle switch and throttle position sensor are used to inform the computer of throttle position and engine load. When the throttle is closed, the AIS controls idle speed by moving the throttle linkage stop. When the throttle is open, the position sensor enables the computer to vary enrichment. If the throttle is floored and the engine is not running, no fuel will flow (to help prevent flooding).