Fuel Pump: Description and Operation

Fuel Pump:

The fuel pump is a gear/rotor type driven by a permanent magnet, 12 volt electric motor that is immersed in the fuel tank. The fuel pump module also contains the fuel gauge sending unit. The fuel pump utilizes a check valve at the outlet tube that consists of a check ball and spring. When the pump is not operating spring pressure holds the valve closed, preventing fuel from flowing back through the pump. When the pump is operating fuel pressure forces the ball off its seat allowing fuel to flow. Fuel system operating pressure is maintained at 97-103 kPa (14-15 psi) by the fuel pressure regulator, while the pump is operating, and drops to zero when the pump is not operating.