Deceleration Valve: Testing and Inspection

1. Disconnect hose from throttle closer.
2. Raise and support front of vehicle, block rear wheels and apply hand brake.
3. Place shift lever in second gear and check for vacuum at disconnected hose with vehicle speed above mph and engine speed above 800 RPM.
4. If there is vacuum, proceed to step 18.
5. If there is no vacuum, check for voltage at throttle closer solenoid valve with vehicle speed above mph and engine speed above 800 RPM.
6. If there is no voltage, proceed to step 10.
7. If there is voltage, disconnect vacuum hose from throttle closer solenoid valve and check for vacuum.
8. If there is vacuum, replace throttle closer solenoid valve and repeat test.
9. If there is no vacuum, check vacuum line to throttle closer solenoid valve for leaks or blockage, and carburetor port for blockage. Clean or repair as necessary and repeat test.
10. If there was no voltage in step 5, turn ignition key to "ON" and check for voltage between orange terminal of throttle closer control unit connector and body ground.
11. If there is voltage, check clutch switch, adjust or replace as necessary, and repeat test.
12. If there is no voltage, check for voltage between yellow/green terminal of throttle closer control unit and body ground with vehicle speed above mph.
13. If there is voltage, check blue wire between control unit and distributor and, if wire is satisfactory, replace control unit and repeat test.
14. If there is no voltage, check input voltage of vacuum switch with vehicle speed above mph.
15. If there is no voltage, check fuse, wiring, and speed sensor, repair or replace as necessary, and repeat test.
16. If there is voltage, disconnect hose No. 20 from vacuum switch and check if vacuum is above 5.9 in. Hg. with vehicle speed above mph.
17. If vacuum is below 5.9 in. Hg. check vacuum line to vacuum switch for leaks or blockage and carburetor port for blockage. Clean or repair as necessary and repeat test.
18. If vacuum is above 5.9 in. Hg., check wiring between vacuum switch and control unit and, if wiring is satisfactory, replace vacuum switch and repeat test.
19. Connect vacuum pump to throttle closer and apply approximately 15.7 in. Hg. of vacuum with engine idling.
20. If engine does not stop, check throttle closer linkage and throttle cable for binding or improper adjustment.
21. If throttle controller linkage and throttle cable are satisfactory, replace throttle closer and repeat test.