Fuel Pump: Description and Operation

FUEL PUMP ASSEMBLY (WITH FUEL FILTER, LEVEL GAUGE (SENSOR) AND FUEL CUT VALVE)
The fuel pump assembly consists of fuel pump, fuel filter, fuel level sensor and fuel cut valve.

Fuel Cut Valve
The fuel cut valve consists of a float and a spring. It allows only the fuel vapor to flow into the canister and prevents the fuel from flowing into the canister.





FUEL PUMP
The electric fuel pump located in the fuel tank consists of armature, magnet, impeller, brush, check valve, etc.. The ECM (PCM) controls its ON/OFF operation as described under "Fuel Pump Control System"

Operation
When power is supplied to the fuel pump, the motor in the pump runs and so does the impeller.
This causes a pressure difference to occur between both sides of the impeller as there are many grooves around it. Then the fuel is drawn through the inlet port, and with its pressure increases it is discharged through the outlet port.
The fuel pump also has a relief valve to prevent excessive rise of the discharge pressure and a check valve to keep some pressure in the fuel feed line even when the fuel pump is stopped.