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,

• Check pulse signal at engine control unit.
• Check vacuum sensor operation.
• Check coolant thermosensor operation.

If dwell meter reading is 27 degrees,

• Check intake air thermosensor operation.
• Check vacuum hose routing.
• 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,

• Check vacuum hose routing.
• Check O2 sensor operation.
• Check air/fuel solenoid valve and wiring harness.
• Check carburetor jets and air bleeds.

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