Procedure at Idle

The ignition timing can also be adjusted according to the following alternate procedure.
The alternate timing procedure does not require that the engine speed be increased to 1600 rpm.
Preparation:
- Set the parking brake.
- Shift automatic transmissions to PARK and manual transmissions to the neutral position.
- Start the engine and allow it to attain normal operating temperature.
- Ensure that the A/C is turned OFF, if equipped.
Procedure:
- With the ignition switch OFF, connect an ignition timing light and a calibrated, expanded scale tachometer.

NOTE: If the timing light has an adjustable advance control feature, turn the control to the OFF position.

- Disconnect the four-inch Hg vacuum switch hose (located at the top of the cylinder head cover) and plug the hose opening.

NOTE: The four-inch Hg vacuum switch has black and red wires connected to it.

- Disconnect the distributor vacuum advance hose and connect the hose to the four-inch Hg vacuum switch.
- Disconnect the knock sensor wire connector and connect the wire connector to the cylinder block (ground) with a jumper wire.

NOTE: Grounding the knock sensor wire connector prevents electromagnetic interference (EMI) from causing erroneous reactions by the FFB system micro computer unit (MCU).

WARNING: Use extreme caution when the engine is operating. Do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or the fan. Do not wear loose clothing.

- Start the engine.
- With the engine at idle speed, check the timing.
- Adjust the timing one degree higher than the specification listed on the Emission Control Information label.










- Also, refer to the ignition advance curve illustrations.
- Tighten the distributor hold-down clamp and verify that the ignition timing is correct.
- Turn the engine OFF and remove the timing light and tachometer.
- Connect the number one spark plug wire, if disconnected.
- Connect the hose to the distributor vacuum advance mechanism.
- Connect the wire connector to the vacuum switch assembly.

NOTE: With the alternate timing procedure, the basic timing must be one degree higher than the specification listed on the Emission Control Information label. For example, if the timing specification is listed as 6 Degrees plus or minus 2 degrees at 1600 rpm, the alternate procedure requires 7 degrees plus or minus 2 degrees at idle speed.