Fuel Pump: Description and Operation

Fig. 1 Electric fuel pump & sender assembly. 1984 - 87 Ford:

Fig. 2 Fuel pump wiring diagram. 1984 V8-460 models w/single fuel tanks:

Fig. 4 Fuel pump wiring diagram. 1984 V8-460 models w/dual fuel tanks:

1984 V8-460 ENGINE & HOT FUEL HANDLING SYSTEM

The in-tank high pressure fuel pump, used on 1984 models, is capable of supplying approximately 26 gallons of fuel per hour at 40 psi. Fig. 1. The pump incorporates an integral relief valve that opens at 120 psi in the event of fuel system over-pressure due to restricted fuel flow.
On vehicles with single fuel tanks, the electrical system, Fig. 2, provides power to the pump through two relays: starter relay and fuel pump cut-off relay. On vehicles with dual fuel tanks, the electrical system, Fig. 4, provides power to the pump through three relays: starter relay, fuel pump cut-off relay and fuel tank selector relays. On all vehicles, the current path is dependent on operating conditions.
In the event of a collision, the inertia switch contacts open and the fuel pump automatically shuts off, even if engine operation continues. The engine will stop a few seconds after fuel pump operation stops and cannot be restarted until the inertia switch is manually reset. The inertia switch is located behind the instrument panel.