Main Air Jet Control System

1. Remove air cleaner cover and filter element.
2. Disconnect hose from main air jet solenoid valve, then install a suitable hand vacuum pump to the solenoid valve.
3. Start engine and allow to reach normal operating temperature, then draw vacuum at idle.
4. If vacuum is not present, proceed to step 6. If vacuum is present, check for voltage at main air jet solenoid valve.
5. If voltage is present, refer to Troubleshooting. If voltage is not present, replace solenoid valve and repeat test.
6. Disconnect vacuum hose No. 2 from control box No. 1, then draw vacuum at idle. Vacuum should remain steady.
7. If vacuum remains steady, test is complete. If vacuum is not present, check for voltage at main air jet solenoid valve.
8. If voltage is not present, refer to Troubleshooting. If voltage is present, replace solenoid valve and repeat test.



Troubleshooting
1. Check vacuum switch for proper operation.
2. Test 10 or 15 mph speed sensor as outlined under ``Speed Sensor, Test'' procedure.
3. Turn ignition switch on and check for voltage at black/yellow wire at control unit connector. If there is no voltage, check wiring.
4. Check black or brown/black wire for continuity between control unit and suitable ground. There should be continuity.
5. Check air intake temperature sensors for proper operation. Replace as required.
6. If no faults were found, replace control unit and repeat test.