Idle Control System

Fig. 46 Idle Control System:

The idle speed of the engine is controlled by the Electronic Air Control Valve (EACV) and the fast idle valve. The valve changes the amount of air bypassing into the intake manifold in response to electric current sent from the ECU. When the EACV is activated, the valve opens to maintain the proper idle speed. The devices that directly effect the idle control system are:

1. Air Conditioning Signal
This signals the PGM-FI ECU to increase engine idle rpm when there is a demand from the air conditioning circuits (A/C switch).

2. Alternator (FR) Signal
This signals the PGM-FI ECU to increase the engine rpm when the alternator is charging the battery.

3. Automatic Transmission Shift Position Signal
This signals the PGM-FI ECU when the transmission is in neutral or park.

4. Power Steering Oil Pressure Signal
This signals the PGM-FI ECU when the power steering load is high.

5. Starter Signal
This signals the PGM-FI ECU when the engine is cranking. The ECU controls the idle control solenoid valve to promote easy starting.