Idle Speed

NOTE: Because the idle speed is controlled automatically by the engine control unit through the idle speed control (ISC) solenoid valve, usually it is not necessary to check and adjust the idle speed. However, when the test connector (Green: 1-pin) is grounded it disables the ECU control of the idle speed. If rough idling due to low idle speed occurs when the test connector is grounded, the idle speed should be adjusted. If a turbocharged vehicle is experiencing an unstable idle (hunting) after cold starts, refer to the COMPUTERIZED ENGINE CONTROLS section.

1. Check the condition of the engine (spark plugs, leaks in hoses, etc.).
2. Turn all electrical loads OFF.
3. Warm up the engine and run it for three minutes at 2,500-3,000 rpm
in neutral or park.

Fig. 38 Black Test Connector:

4. Connect a tachometer to engine.

a) Connect a tachometer to the check connector at the trailing side coil with igniter.
b) If the tachometer does not function properly on the trailing side coil with igniter, reconnect to the leading side coil with igniter (black connector).
c) If using an inductive (secondary pickup) type tachometer, connect it only at the trailing side high tension leads. If connected on the leading side coil with igniter, it will function incorrectly.

Fig. 37 Test Connector:

5. Ground the test connector (green: 1-pin) with a jumper wire.
6. Check that the idle speed is within specification.

Idle speed
750 ± 25 rpm

7. Check the throttle sensor (Refer to COMPUTERIZED ENGINE CONTROLS).

Fig. 38 Idle Adjustment:

8. If the idle speed is not within specification, remove the blind cap from the solenoid valve (Bypass air control) and adjust the idle speed by turning the air adjust screw.


9. After adjusting the idle speed, install the blind cap and disconnect the jumper wire from the test connector.