Fuel Pump: Description and Operation

Fuel Pump:

PURPOSE
Provides pressurized fuel to the TBI system.

LOCATION
The fuel pump is submerged in the fuel tank.

OPERATION
When the key is turned ON the ECM will energize the fuel pump relay, which in turn energizes the fuel pump. The pump will remain ON as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

If the ECM does not receive ignition pulses, it will turn the relay OFF after two (2) seconds after key ON.

As a back-up system, the fuel pump can also be turned "ON" by the oil pressure switch. If the fuel pump relay fails, the oil pressure switch will run the fuel pump. However, an inoperative relay can result in long cranking times, especially if the engine is cold. The switch will not turn the pump "ON" until oil pressure reaches about 28 kPa (4 psi).

CONSTRUCTION
It consists of a motor, a vane roller pump, a fuel damper, and a check valve to prevent pressure bleed-off when the engine is off.