I

IDLE - A low engine speed, sufficient to keep the engine running smoothly when a car is at rest. Also called "hot idle, curb idle, or idle speed."

IDLE LIMITER - A fitting on the idle/air mixture screw that limits the adjustment of the idle mixture to prevent it from being set so rich that the exhaust would contain excessive air pollutants. Limiters were used until the idle mixture adjusting screws were made tamper resistant (capped), beginning in 1979 on some cars.

IDLE MIXTURE - The specific mixture of air and fuel supplied to an engine at idle.

IDLE-MIXTURE SCREW - An adjusting screw that leans or enriches the idle mixture. See also "idle limiter."

IDLE SPEED - See "idle"

IDLE SPEED CONTROL (ISC) - An actuator mounted to the fuel charging assembly which controls the idle speed. The ISC functions as high cam rpm, anti-diesel shut off, dash pot and prepositioning for next vehicle start. ISC is driven by the ECA and includes an integral idle tracking switch (ITS).

DC MOTOR IDLE SPEED CONTROL:

IDLE SPEED CONTROL (ISC) - Device used on some carburetors to maintain idle speed in relation to engine temperature and accessory load.
IDLE-SPEED SOLENOID - Electromechanical device with a plunger that bears against the throttle linkage to hold the idle speed. When the ignition is turned off, the plunger is retracted by a spring and the throttle closes completely so that the engine will not stall. See "Throttle solenoid positioner."


IDLE SYSTEM - The special components of the carburetor or fuel-injection system that are used only when the engine is idling.


IDLE TRACKING SWITCH (ITS) - An onboard component of the idle speed control motor that determines when the throttle is at idle.


IDLE VACUUM VALVE (IVV) - This device may be used in conjunction with other vacuum controls to dump thermactor air during extended period of idle. Provides protection to the catalyst.