Low Pressure Fuel Pump Test

STANDARD PROCEDURE - LOW PRESSURE FUEL PUMP TEST

NOTE: Assure fuel tank quantity and proper fuel gauge operation. Assure that the fuel pump fuse or relay is not open. Capture any fuel spillage and store in appropriately marked containers.

NOTE: When the ignition switch is turned to the ON position the fuel pump will begin to run for 20-30 seconds and then it stops.

The low pressure pump draws fuel out of the fuel tank module and pushes the fuel towards the fuel filter. If the pressure reading is below specification, look for damaged or leaking fuel lines or a restricted fuel filter. If no problem is found with the fuel system replace the low pressure fuel pump.

1. Disconnect the negative battery cable.
2. Connect a fuel gauge to the low pressure fuel supply to the high pressure pump.




3. Connect negative battery cable.
4. Turn the ignition to the ON position and observe the fuel gauge reading.




5. The fuel pressure should be 4.0 to 4.5 bar (58 - 65 psi) If the fuel pressure is below specification, move the gauge to the fuel filter input line and re-test.




6. If the fuel pressure is still below specification, replace the fuel pump. If the fuel pressure is within the specification, replace the fuel filter and retest at the high pressure pump to verify system function.