Component Tests and General Diagnostics

Fig. 3 Air/fuel solenoid check connector.:

1. Run engine until normal operating temperature is reached and continue to run at idle.
2. Connect dwellmeter to air/fuel solenoid brown/yellow check connector, Fig. 3, and note dwellmeter reading.
3. If dwellmeter reading is fixed at 0°, check the vacuum sensor, water thermo sensor and ignition pulse signal to the emission control unit.
4. If dwellmeter reading is fixed at 27°, check vacuum hose routing, oxygen sensor and intake air temperature sensor.
5. If dwellmeter reading is fixed at 36°, check water thermo sensor.
6. If dwellmeter reading fluctuates between 20° and 70°, check vacuum hose routing, oxygen sensor, air/fuel solenoid valve and wiring harness, and carburetor jets and air bleeds. If all items are satisfactory, adjust idle mixture.