Mixture Control Solenoid: Testing and Inspection
Inspection of Valve1. Warm up engine and run at idle.
Fig. 3 Air/fuel solenoid check connector.:
2. Connect a dwell meter to the A/F check connector (Br/Y) and check to see that the dwell meter indicates within 20°-70°.
3. Using a jumper wire, ground the A/F check connector and check to see that the engine speed drops.
4. If it does not, clean the A/F solenoid valve or replace the valve.
Note: Clean with carburetor cleaner spray and blow out with compressed air, but do not submerge in cleaner. For valve replacement parts information, see TSB.
Fig. 3 Air/fuel solenoid check connector.:
Inspection of Signal
1. Run engine until normal operating temperature is reached and continue to run at idle.
2. Connect dwellmeter to brown/yellow check connector.
3. Disconnect and plug vacuum hose from vacuum sensor, then connect a hand vacuum pump to the sensor.
4. Apply 19.7 inHg vacuum to sensor and ensure dwellmeter indicates 20° - 70°.
5. Release vacuum and ensure dwellmeter indicates 0°. If reading is not as specified, check IE terminal voltage of the emission control unit and the vacuum sensor.
6. Remove vacuum pump and reconnect vacuum hose.
7. Accelerate engine to 4500 rpm and ensure dwellmeter indicates a fixed 0°. If reading is 72°, check idle switch and neutral switch. If reading is anything other than 0° or 72°, replace emission control unit.