Transmission Controlled Vacuum Advance

With engine warm, disengage clutch and race the engine. Pull off vacuum hose from distributor. If vacuum is felt at top gear position and is not felt at other positions, operation is satisfactory. Vacuum should always be felt at temperatures below 50°F (before engine is warmed up). If operation is not satisfactory, one of the following may be the cause:

1. Air leakage due to poor connection of vacuum tube.
2. Malfunction of transmission switch.
3. Malfunction of temperature sensing switch.
4. Blown fuse or poor electrical connection.