Idle Speed Control System

An electrically governed idle rpm control valve keeps the idle speed stable under the various engine operating conditions. Measured intake air from the air flow meter by-passes the throttle plate through the idle rpm control valve and subsequently calls for additional fuel injection. The amount of by-pass air is determined by the variable orifice of the control valve.

An additional electronic control unit, the "Idle Speed CU", controls the orifice opening according to the engine speed and the engine operating conditions as related to engine coolant temperature, transmission, air conditioning, and heater intake air temperature.