Main Relay (Computer/Fuel System): Description and Operation

Auto Shutdown (ASD) Relay:

PURPOSE
Relay supplies battery voltage to the ignition coil and fuel injectors, when grounded by the engine controller.

OPERATION
The engine controller grounds the relay when the ignition switch is in the START or RUN position and the engine controller is receiving reference signals from the distributor pick-up.

If the engine controller does not receive a signal from the distributor pick-up, (engine not running), the engine controller interrupts the relay ground and no voltage is supplied to the ignition coil, or fuel injectors.

NOTE: The engine controller controls the Auto Shutdown (ASD) and fuel pump relays simultaneously, through the same ground circuit.