Base Idle Speed

Fig. 54 Connecting A Tachometer To The Engine Speed Terminal:

1. Confirm initial inspection conditions:

a. Engine coolant temperature is 185 - 205°F.
b. Lights, cooling fan and all accessories are OFF.
c. Transaxle is in neutral or park.
d. Steering wheel is in straight-ahead position, (on vehicles with power steering).

2. Check the ignition timing and adjust, if necessary. (Refer to procedure)
3. Connect a tachometer to the engine speed detection connector, Fig. 54. Do not unplug the connector.
4. Start the engine and idle for 2 minutes.
5. Check the engine idle speed. If it is NOT within specifications, check the idle speed control system.

Curb Idle Speed: 750 ± 100 RPM

6. Stop engine and disconnect tachometer. (Leave tachometer connected, if further adjustments are required).

Fig. 55 Idle-Speed Control Servo Connector:

IDLE SPEED CONTROL (ISC) SYSTEM

1. Loosen the accelerator cable, so a slight amount of slack is present.
2. Connect a tachometer to the engine speed detection connector.
3. Turn the ignition switch ON, but DO NOT start the engine.
4. Wait at least 15 seconds and check the idle speed control plunger position. The plunger should extend to a fast idle position, then retract after 15 seconds. This is the initial position.
5. Turn the ignition switch OFF and disconnect the electrical connector for the idle speed control servo. This will lock the idle speed control plunger at the initial position. Fig. 55
6. Loosen the fixed speed adjusting screw (SAS) fully.
7. Start the engine and check that the idle speed is within specifications.

Basic Idle Speed: 750 ± 50 RPM

Fig. 56 Idle-Speed Control Adj. Screw (Viewed From Above Engine):

8. If idle speed is not as specified, adjust the idle speed control adjusting screw with a hexagon wrench. Fig. 56
9. Turn the fixed SAS in until the engine speed rises slightly.
10. Back-off the SAS to the "touch point", where the engine speed ceases to decrease.
11. Back-off the SAS an additional half turn from the "touch point".
12. Stop the engine. Readjust the accelerator cable.
13. Reconnect the electrical connector for the idle speed control servo and remove the voltmeter from the engine.
14. With the ignition switch OFF, disconnect the negative battery terminal for at least 15 seconds. This will clear any diagnostic codes that may have occurred during testing.
15. Reconnect the battery, start the engine and check that the engine is operating in the normal idle range.