Installation and fault finding

EMS Caution UK

As gasoline is involved when working on the Fuel Pump, work in a ventilated area away from open flame.

  • Relieve fuel system pressure before starting the replacement procedure, and refer to car maker’s instructions for specific steps.
  • Drain tank, loosen tank straps and lower the tank; or locate the service hole in the boot; or disconnect the rear seat cushion (some vehicles have a removable access panel to the Fuel Pump module, allowing Fuel Pump replacement without removing the tank).
  • Disconnect Fuel Pump module connector
  • Disconnect fuel tank main tube
  • Remove Fuel Pump module from fuel tank
  • Remove fuel suction support 
  • Remove fuel pressure regulator if necessary
  • Remove strainer
  • Remove fuel suction plate and disconnect the Fuel Pump connector or wiring
  • Remove Fuel Pump

For installation, perform the removal steps above in reverse order. To check for fuel leaks refer to the car maker’s instructions.

Possible failures 

The most common cause of in-tank electric Fuel Pump failures is fuel tank contamination due to dirt and rust. Therefore it is essential that a replacement Fuel Pump should be installed into a clean fuel tank.

Another common cause of in-tank electric Fuel Pump failures is faulty electrical connections such as loose connections, poor grounds or low voltage to the pump due to overheated connectors.

  • No initial combustion: No combustion occurs due to no operation or difficult start-up
  • Stalling: Engine stalls shortly after startup due to no operation; or engine stalls when accelerator is depressed.
  • Poor drivability: Hesitation during acceleration due to decreased flow quantity; insufficient output caused by no increase in fuel pressure; engine backfires; or abnormal knocking.
Prevention and Solutions 

It is very important to make a correct diagnosis before installing a new Fuel Pump. This is because the real root cause might be another component than the Fuel Pump, such as a clogged strainer, contaminated fuel filter, faulty fuel gauges or even very low levels of fuel in the fuel tank. To help prevent Fuel tank problems:

  • The Fuel Pump and fuel system should be maintained in good condition
  • The vehicle should not be driven with a nearly empty fuel tank
  • Attention should be paid to the fuel quality and octane level
  • The fuel filter should be checked periodically and replaced before its service life is up
  • Fuel hoses and electrical connections should be regularly checked for cracks, leaks and any other defects
  • If the Fuel Pump needs to be replaced, ensure the fuel system is clean and the fuel tank is free from contaminants