Del Sol L4-1.6L SOHC (VTEC) (1994)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
Idle Air Control Valve Description
PURPOSE
The Idle Air Control (IAC) is used to provide a cold fast idle as well as a stable idle under various operating conditions and loads.
OPERATION
The IAC Valve is a linear solenoid valve, with adjustable air passages, mounted on the intake manifold. The IAC is powered by ignition switch
terminal, IGN. 1, and receives power anytime the ignition is turned ON. The Engine Control Module (ECM) controls the ground circuit. The valve is
used to correct idle speed when out of normal operating parameters. Idle speed is modified by allowing air to bypass the throttle plate. By varying the
current of the signal to the IAC the ECM is able to control the position of the IAC plunger.
After the engine starts, the IAC Valve opens for a certain time. The amount of air is increased to raise the idle speed about 150-300 rpm.
When the engine coolant temperature is low, the IAC Valve is opened, allowing air to be bypassed to the intake manifold and the Fast Idle Thermo
Valve is open and allows air to bypass the throttle plate. The amount of bypassed air is thus controlled in relation to the engine coolant temperature, to
obtain the proper fast idle speed.