Idle-Up Throttle Opening Valve

Throttle Opening System (Throttle Opener Solenoid For A/C):

THROTTLE OPENING SYSTEM (FOR A/C)

When the air conditioner relay is turned on and the engine speed is below the set speed (1,200 RPM), the ECU provides a ground to the throttle opener solenoid valve. The throttle opener solenoid valve is energized and introduces intake manifold vacuum to the throttle opener. The throttle valve opens slightly and prevents engine speed drop caused by air conditioner load.

Throttle Opening System:

IDLE UP SYSTEM (FOR ELECTRICAL LOAD)


When the engine speed drops below the set speed (1,200 RPM), the ECU provides a ground to the idle up solenoid valve. When the electrical switch is turned on for lighting (tail light switch) or the blower (fan, heater or defroster), the idle up solenoid valve is energized, allowing intake manifold vacuum to the idle up Actuator to open the throttle valve slightly, preventing engine speed drop caused by electrical load. In addition, independently from the ECU, if the power steering oil pressure switch is activated (indicating a load) the idle up control solenoid valve is energized to introduce intake manifold vacuum to the idle up Actuator. The throttle valve opens slightly, preventing engine speed drop caused by power steering load.
The Idle up actuator does secondary duty as a throttle closing Dash Pot under deceleration conditions. To accomplish this there is an adjustment screw (SAS 3) to limit the additional opening of the throttle. When the engine vacuum is higher than normal idle vacuum, the idle up actuator pulls the throttle open the additional amount allowed by SAS 3.