Throttle Closer Valve Test

Cold Engine

1. Ensure that coolant temperature is below 158°F.
2. Disconnect air suction lower hose at anti-afterburn valve.
3. Start engine and quickly raise engine speed to 2500 RPM, then quickly close throttle.
4. If there is no vacuum, proceed to step 11.
5. If there is vacuum, check for voltage at anti-afterburn control solenoid valve.
6. If there is no voltage on Prelude models, refer to Troubleshooting. If there is no voltage on Accord models, check for continuity between speed sensor and thermosensor wire terminals. If continuity is not present, replace thermosensor. If continuity is still not present, replace speedometer/speed sensor.
7. If there is voltage, disconnect vacuum hose from anti-afterburn valve and check for vacuum at hose.
8. If there is no vacuum, check for leaks or disconnected hose.
9. If hoses are satisfactory, replace anti-afterburn control solenoid valve and repeat test.
10. If there was vacuum in step 7, replace anti-afterburn valve and repeat test.
11. Raise and support front of vehicle, block rear wheels and apply parking brake.
12. Place shift lever in second or ``2'' position and accelerate, then quickly release throttle and check for vacuum during deceleration above 15 mph on all models except 1985-87 Prelude with manual transmission or 3000 RPM on 1985-87 Prelude models with manual transmission.
13. If there is vacuum, perform hot engine test.
14. If there is no vacuum, check for voltage at anti-afterburn control solenoid valve above 15 mph.
15. If there is voltage on Prelude models, refer to Troubleshooting. If there is voltage on Accord models, replace speed sensor.
16. If there is no voltage, disconnect vacuum hose from anti-afterburn valve and check for vacuum above 15 mph on all models except 1985-87 Prelude with manual transmission or 3000 RPM on 1985-87 Prelude models with manual transmission.
17. If there is vacuum, replace anti-afterburn control valve and repeat test.
18. If there is no vacuum, disconnect vacuum hose from anti-afterburn valve and check for vacuum at hose.
19. If there is no vacuum, check for leaks or disconnected hose and repeat test.
20. If there is vacuum, replace anti-afterburn valve and repeat test.
21. Perform hot engine test.

Hot Engine

1. Ensure that coolant temperature is above 158°F.
2. Disconnect air suction lower hose at anti-afterburn valve.
3. Start engine and quickly raise engine speed to 3500 RPM, then quickly close throttle.
4. If there is no vacuum, check for voltage at anti-afterburn control solenoid valve.
5. If there is voltage on Prelude models, refer to ``Troubleshooting, 1984-86 Prelude.'' If there is voltage on Accord models, replace thermosensor.
6. If there is no voltage, replace anti-afterburn control solenoid valve and repeat test.