Distributor Vacuum Control: Testing and Inspection

1. Warm engine to operating temperature.
2. Ensure idle speed and ignition timing are within specification.
3. Disconnect vacuum hose(s) to vacuum control and plug end of hose(s).
4. Attach vacuum pump to control A and check with timing light while applying vacuum.

Fig. 27 Vacuum spark advance chart. Non-turbocharged:

5. Attach vacuum pump to control R only and check with timing light while applying vacuum Fig. 27.
6. Reconnect vacuum hose(s).