Cold Engine
Mixture Control System TestCOLD ENGINE
1. Disconnect the air suction lower hose at the anti-afterburn valve.
2. Check for vacuum at idle.
There should be no vacuum.
- If there is vacuum, replace the anti-afterburn valve and retest.
3. Check for vacuum at #31 hose.
There should be vacuum.
- If there is vacuum, go on to step 4.
- If there is no vacuum, go to [1][2]Control Unit Output Troubleshooting/Anti-afterburn Control Solenoid Valve. Component Tests and General Diagnostics
4. Block rear wheels and set the parking brake. Jack up the front of the car and support with safety stands.
5. Place the shift or selector lever in second or 2 position and accelerate, then suddenly release the throttle and check for vacuum during deceleration above 15 mph.
There should be vacuum.
- If there is vacuum, go on to Hot Engine inspection.
- If no vacuum, disconnect #31 vacuum hose at the anti-afterburn valve and check for vacuum at #31 hose above 15 mph.
- If there is no vacuum, replace the anti-afterburn valve and retest.
- If there is vacuum, go to [1][2]Control Unit Output Troubleshooting/Anti-afterburn Control Solenoid Valve. Component Tests and General Diagnostics