System Test

Fig. 37a Connecting Vacuum Gauge To Sub-Diaphragm:

A/T AND M/T MODELS

1. Disconnect the vacuum hose from the distributor vacuum advance sub-diaphragm and connect a vacuum gauge to the end of the hose. Fig. 37a
2. Make sure the coolant temperature is below 77°F and start the engine.
3. Increase and decrease the engine speed using the throttle valve. The vacuum gauge should maintain a steady reading.
4. Allow the coolant temperature to exceed 106°F and repeat step 3.
5. The vacuum should be 15 - 18 in.Hg at idle and drop as the engine speed is increased.
6. If the system does not perform as specified, test each component of the spark control system.
7. Remove the vacuum gauge from the engine and reattach the vacuum hose to the sub-diaphragm.

Fig. 37b Connecting Vacuum Gauge To Main Diaphragm:

M/T MODELS ONLY

1. Disconnect the vacuum hose from the distributor main vacuum advance diaphragm and connect a vacuum gauge to the end of the hose. Fig. 37b
2. Make sure the coolant temperature is below 104°F and start the engine.
3. Increase and decrease the engine speed using the throttle valve. The gauge should indicate zero vacuum.
4. Allow the coolant temperature to exceed 129°F.
5. The vacuum should be zero at idle and increase to 15 - 18 in.Hg as the engine speed is raised to 2,500 rpm.
6. If not as specified, test the (B) BVSV.
7. Remove the vacuum gauge from the engine and reattach the vacuum hose to the main diaphragm.