H. Adjust Idle Speed & Basic Timing & Test O2 Sensor Output

1. Start the engine and warm it to normal operating temperature.

2. Run the engine for at least five seconds between 2000 and 3000 RPM.





3. Using a tachometer, check the idle speed. If it is not between 650 - 850 RPM, readjust it to 750 RPM using idle speed adjusting screw No. 1 (SAS-1), (Figure 17).

4. After the idle speed has been verified, adjust the basic ignition timing to 8° BTDC using the Service Manual Procedure.

NOTE:
This is a new basic timing specification.

Recheck the idle speed and adjust if necessary.





5. Connect the positive lead of a digital volt-ohm meter to the oxygen sensor check terminal (Figure 18). Connect the negative lead to a good ground on the engine block.

NOTE:
The oxygen sensor check terminal has two electrical connectors. Connect the positive lead of the volt-ohm meter to the connector with the shielded wire. If the voltmeter reads zero volts connect the positive lead to the other connector and recheck.

6. Note the maximum oxygen sensor voltage. If the maximum voltage is less than 0.6 volts, replace the oxygen sensor as follows:

a. Turn off the engine.

b. Disconnect the oxygen sensor electrical connector.

c. Remove the heat shield from around the exhaust manifold.

d. Remove the oxygen sensor.

e. Install a new oxygen sensor Part No. MD117240.

f. Reinstall the heat shield.

g. Reconnect the oxygen sensor electrical connector.