Bump Switch
This explains how start up works.
For bumping we really don't want the power to go to the ignition.
So leaving the key in off and using an external switch across the Bat and Sol terminals works well.
When the key is turned to start, here what happens:
Initially current flows through the key switch and wire S2 to the starter relay and back to ground (through NSS for automatics).
Whenever the distributor points are closed current flows through J3 to the coil, and back to ground.
Next, the energized relay closes the connection between Bat & Sol on the relay.
Current flows from the battery to the starter's solenoid..
Then starter will connect and draw power.
Current returns through the grounds.
This explains how start up works.
For bumping we really don't want the power to go to the ignition.
So leaving the key in off and using an external switch across the Bat and Sol terminals works well.
When the key is turned to start, here what happens:
Initially current flows through the key switch and wire S2 to the starter relay and back to ground (through NSS for automatics).
Whenever the distributor points are closed current flows through J3 to the coil, and back to ground.
Next, the energized relay closes the connection between Bat & Sol on the relay.
Current flows from the battery to the starter's solenoid..
Then starter will connect and draw power.
Current returns through the grounds.
