ENGINE AND EMISSION CONTROL PARTS DESCRIPTION

The ignition signal from the E.C.U. is amplified by the power transistor, which turns the ignition coil primary circuit on and off, inducing the proper high voltage in the secondary circuit.

The air regulator provides an air by-pass when the engine is cold for a fast idle during warm-up. A bimetal, heater and rotary shutter are built into the air regulator. When the bimetal temperature is low, the air by-pass port opens. As the engine starts and electric current flows through a heater, the bimetal begins to turn the shutter to close the by-pass port. The air passage remains closed until the engine stops and the bimetal temperature drops.

The I.A.A. unit is made up of the A.A.C. valve, F.I.C.D. solenoid valve and idle adjust screw. It receives the signal from the E.C.U. and controls the idle speed at the preset value. The F.I.C.D. solenoid valve compensates for changes in idle speed caused by the operation of the air compressor.

The E.C.U. actuates the A.A.C. valve by an ON/OFF pulse. The longer that ON duty is left on, the larger the amount of air that will flow through the A.A.C. valve.

The vehicle speed sensor provides a vehicle speed signal to the E.C.U. The speed sensor consists of a reed switch and a speedometer pinion, which are installed in the transmission, and transforms vehicle speed into pulse signals.