Fuel Pump: Description and Operation

Fuel Pump:

PURPOSE
The Fuel Pump, located inside of the fuel tank, supplies a constant pressurized flow of fuel for fuel injection operation. When the engine is turned off, the Fuel Pump check valve maintains residual fuel pressure for easy starting.

OPERATION
The Fuel Pump utilizes a DC-motor driven impeller and uses the pump casing as the pumping chamber. When the engine is started, the main relay activates the pump. Fuel entering the inlet port flows inside the motor from the pumping chamber and is forced through the discharge port via the check valve. The check valve maintains residual pressure after pump shutdown so the fuel system stays pressurized even when the engine is not running. If fuel flow is obstructed at the discharge side of the fuel line, the relief valve will open to bypass the fuel to the inlet port and prevent excessive fuel pressure.