Mixture Control Solenoid: Testing and Inspection

INSPECTION OF VALVE

1. Warm up the engine and run it at idle.

Checking Dwell:

2. Connect a dwellmeter to the check connector (White:1-pin) and check to see that the dwellmeter indicates within 20°-70°.

Check Connector Grounded:

3. Using a jumper wire, ground the check connector (White:1-pin) and check to see that the engine speed drops.
4. If it does not, clean the air/fuel solenoid valve or carburetor, or replace the air horn assembly.

NOTE: Clean with carburetor cleaner spray and blow out with compressed air, but do not submerge in cleaner. The air/fuel solenoid must be replaced along with the air horn. The air/fuel solenoid is not available separately.

INSPECTION OF SIGNAL

1. Warm up the engine and run it at idle.
2. Connect a dwellmeter to the check connector (White:1-pin).

Testing Vacuum Sensor:

3. Disconnect the vacuum hose from the vacuum sensor and plug it.
4. Connect a vacuum pump to the vacuum sensor.

Dwell Meter Range:

5. Apply 500 mmHg (19.7 inHg) vacuum and check to see the dwellmeter indicates within 20°-70°.
6. Release the vacuum, and check to see the dwellmeter indicates a fixed 0°.
7. If not correct, check the IE terminal voltage of the emission control unit and the vacuum sensor.
8. Remove the vacuum pump, and reconnect the vacuum hose.
9. Increase the engine speed to 4,500 rpm and check to see the dwellmeter indicates a fixed 0°.
10. If the reading is 72°, check the idle switch and neutral switch.
11. If the reading is other than 0° or 72°, replace the engine control unit.