Checking for Signal
- Warm engine to normal operating temperature. Connect a tachometer to engine. Separate vacuum sensing tube (from leading vacuum advance diaphragm to pipe) at pipe. Place a finger over pipe opening and make sure air is not sucked into pipe. See Fig 1 .
- Gradually increase engine speed and make sure air is sucked into pipe when engine speed is 1000-1200 RPM or more. Decrease the engine speed from 4000 RPM rapidly and make sure air is not sucked into pipe while decelerating. Turn A/C switch on and make sure air is sucked into pipe at idling speed.