Fuel Pump Electrical Circuit

When the ignition is turned on without the engine running, the ECM turns on the fuel pump relay for 2 seconds. This builds up fuel pressure.

If the engine is not started within 2 seconds, the ECM shuts off the fuel pump until engine is cranked. When the engine is cranked, the ECM activates the fuel pump relay again. A backup circuit in the oil pressure sender will operate the fuel pump if the relay fails.

Fuel pump relay is located in the right rear corner of engine compartment on "A" series vehicles. On "E" and "J" series, relay is on the right side fender. "G" series relay is on the left side fender.