Prelude L4-1958cc SOHC (1988)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
Idle Control System
Fig. 2 Idle Control System
This system Fig. 2, used on vehicles with A/C, prevents idle speed from dropping when A/C compressor is turned on.
When compressor is on, manifold vacuum is introduced into the diaphragm chamber of the idle boost controller through the A/C idle boost solenoid
valve which is activated by the compressor clutch switch. The idle controller diaphragm rod is retracted to open the throttle valve a certain amount. The
amount of this throttle valve opening is adjusted with the idle control screw on the idle controller to maintain original idle speed.
When the compressor is off, the A/C idle boost solenoid valve is deactivated to close vacuum passage and the vacuum stored in the controller is
released through the filter on the solenoid valve.
