Electronic Idle Speed Control Systems

Idle speed control system consists of idle speed adjuster, intake air distributor and ECU. Idle speed is held constant by increasing or decreasing amount of extra air injected through insulating sleeve around each fuel injector.

High idle speed is maintained when engine temperature is below 107°F (40°C). Idle speed drops to constant low idle RPM when engine temperature is above 107°F (40°C).

This system maintains constant idle speed by varying amount of air by-passing throttle valve through air control valve. Air control valve is operated by idle speed ECU which receives engine information from throttle switch, coolant temperature sensor, and ignition coil.