Idle Speed: Adjustments

Fig. 3 Diagnostic connectors.:

ALLIANCE, ENCORE, FUEGO & SPORTWAGON W/MULTI-POINT FUEL INJECTION

During the following adjustment, a voltmeter with a minimum input impedance of 20,000 ohms per volt must be used.

1. Start engine and allow to reach normal operating temperature.
2. Connect tachometer to diagnostic test terminals D1-1 and D1-3, Fig. 3.
3. Turn off all accessories, then allow electric cooling fan to cycle on and off.
4. With transmission in Drive (manual transmission in Neutral), turn idle speed adjustment bypass screw inward or outward to adjust curb idle speed to specifications.
5. Remove tamper proof plug to gain access to air/fuel mixture adjusting screw. Screw is located on top of air flow meter housing. Refer to ``Gasoline Fuel Injection'' for tamper proof concealment plug removal procedure.
6. Disconnect oxygen sensor wire connector, then connect voltmeter to diagnostic terminals D2-2 and D2-7, Fig. 3. While performing the following test on Alliance, Encore & GTA models, the fuel pressure regulator vacuum source must be connected.
7. Observe voltmeter. Voltmeter should read between 6 and 7 volts.
8. Reconnect oxygen sensor wire connector. Adjust air/fuel mixture screw to obtain voltage noted in Step 7 plus or minus .5 volts.
9. Readjust curb idle speed, if necessary.
10. Install new tamperproof plug.

Fig. 4 Diagnostic connectors.:

Fig. 5 Adjusting idle speed control motor.:

ALLIANCE, ENCORE & GTA W/THROTTLE BODY FUEL INJECTION

Curb idle speed on vehicles with this type of system is controlled by the idle speed control motor. Adjustment is only necessary to establish the initial position of the plunger after the ISC motor has been replaced.

1. Remove air cleaner assembly.
2. Start engine and allow to reach normal operating temperature.
3. Turn all accessories off, then connect tachometer to diagnostic terminals D1-1 and D1-3, Fig. 4.
4. Turn ignition Off and ensure that plunger moves to fully extended position.
5. Disconnect ISC electrical connector, then start engine.
6. Engine idle speed should now be 3300-3700 RPM. If speed is not as specified, turn hex head adjusting screw, Fig. 5, until idle speed is 3500 RPM.
7. Fully retract ISC by holding closed throttle switch plunger in, while throttle is opened. The closed throttle switch plunger should not touch throttle lever when throttle is returned to closed position. If there is contact, check throttle linkage or cable for binding or damage and repair as necessary.
8. Connect ISC electrical connector.
9. Turn ignition off for 10 seconds and check that ISC has moved to fully extended position.
10. Start engine. Engine speed should be approximately 3500 RPM for a short period of time and should then return to idle.
11. Turn ignition off, then disconnect tachometer.
12. Apply suitable thread locking compound to adjustment screw to prevent movement.
13. Install air cleaner.