How a Fuel Pump Works

how a fuel pump works

 A fuel pump is an integral part of the fuel injection system of the automobile. Responsible for supplying pressure to the fuel injectors this pump is electrical controlled by the car's computer (PCM) using a fuel pump relay. A fuel pressure regulator is used to control the pressure which can be located inside the fuel pump or externally on the fuel rail.

Fuel Pump Location

 Most fuel injection system primary fuel pumps are located inside the fuel tank and have the fuel level sensor connected to the pump housing. Even though this electric motor is submerged in fuel there is no danger of fire due to the lack of oxygen inside the tank. Servicing the pump or level sender requires the removal of the pump which can be done through a service port in the car's body or by removing the fuel tank.

Fuel Pump Features

  • Pressurizes the fuel rail
  • Holds fuel level sensor
  • Positioned inside a fluid sump
  • Features a primary fuel filter

Let's see!

Here is a fuel pump inside the fuel tank after the tank and the service cover have been removed.
fuel pump in tank

Here is the fuel pump being removed for inspection, notice the fuel line and electrical wiring connecting the pump and level sensor.
fuel pump removed

This shows you the primary fuel filter attached to the inlet of the fuel pump.
primary fuel filter

The fuel level sensor it mounted to the body of the fuel pump which features a resistor that adjusts as the fuel level rises and falls.
fuel gauge float

A fuel sump is used to keep the pump in place while helping to corral fuel toward the pump when levels are at a minimum.
fuel pump sump


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