System Inspection

Warm engine to normal operating temperature and run at idle. Connect dwell meter set on 4-cylinder scale to White check connector pin No. 1. See Figure . Note dwell meter reading.

If dwell meter reading is zero degrees,

1. Check pulse signal at engine control unit.
2. Check vacuum sensor operation.
3. Check coolant thermosensor operation.

If dwell meter reading is 27 degrees,

1. Check intake air thermosensor operation.
2. Check vacuum hose routing.
3. Check O2 sensor operation.

If dwell meter reading is 36 degrees,

• Check coolant thermosensor operation.

If dwell meter reading fluctuates above or below 20-70 degrees,

1. Check vacuum hose routing.
2. Check O2 sensor operation.
3. Check air/fuel solenoid valve and wiring harness.
4. Check carburetor jets and air bleeds.

If all systems and components are in good working condition, adjust idle mixture with mixture adjusting screw.