Vacuum Spark Delay Valve: Testing and Inspection

Fig. 8 Spark delay valve:

Checking the spark delay valve.
1. Remove the spark delay valve Fig. 8
2. Connect the vacuum tube to the vacuum pump tester.
NOTE: The direction of the spark delay valve arrow should be pointing away from the tester.
3. Completely shut the other side of the spark delay valve off with thumb.
4. Apply a vacuum of over 500 mm-Hg.

Fig. 6 Federal vehicle (manual trans.) vacuum delay tube:

Fig. 7 Non-Fed. vehicle (manual trans.) vacuum delay tube:

5. Release thumb from valve and check the time required for the vacuum reading to decrease to 100 mm-Hg from 400 mm-Hg. The specified time varies depending on the length of the tube Figs. 6 & 7.

Fig. 16 Testing water thermo valve:

Checking the water thermo valve.
1. Remove the water thermo valve.
2. Immerse the valve in a container with water.
3. Heat up the water gradually and observe the temperature.
4. Blow through the valve and if air flows out at 54°C (129°F) or above, the valve is satisfactory Fig. 16.