Tuesday, July 5, 2011

how to change electric fuel pump and relieve fuel pressure on BMW X5

Fuel Pump


Removal & Installation



  1. Before servicing the vehicle, refer to the Precautions section.
  2. Drain the fuel tank.
  3. Properly relieve the fuel system pressure.
  4. Remove or disconnect the following:

    Negative battery cable
    Rear seat bench
    Rubber plug above the sender unit and fold the rubber mat back
    Metal cover
    Fuel gauge level sending unit electrical connector
    Fuel lines
    Rotary connection with special tool 16-1-020

  5. Raise the fuel level sensor and expose the spiral hose.
  6. Remove the fuel level sensor and fuel pump from the tank.

To install:


NOTE
Always use a new seal or gasket when installing the fuel pump or fuel level gauge sending unit assembly.

  1. Install the fuel pump into the fuel tank, taking care not to bend or damage the fuel sending unit assembly.
  2. Install a new seal and torque the sealing ring using tool No. 16-1-020 as follows:
    1. Metal sealing rings: 26 ft. lbs. (35 Nm).
    2. Plastic sealing rings: 41 ft. lbs. (55 Nm).

  3. Install or connect the following:

    Fuel lines
    Fuel gauge level sending unit electrical connector
    Metal cover
    Rubber plug above the sender unit
    Rear seat bench
    Negative battery cable

  4. Start the vehicle and check for leaks, repair if necessary.

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Relieving Fuel System Pressure


WARNING
Fuel lines are under about 43.5-72.5 psi (3-5 bar) of pressure. Manufacturer does not provide a specific pressure relieving procedure, but instructs that any fuel system disconnect will spill fuel, so be prepared to catch and clean up any spilled fuel.

A safe way to relieve the pressure in the system is to locate the fuel pump relay located on the cowl. Unplug and remove the relay, and place it in a safe location. With the fuel pump relay removed, start the engine and operate it until it stalls. Crank the engine for 10 seconds after it stalls to remove any residual pressure.

To relieve the pressure in the system, locate fuel pump relay located on the cowl. The relay can sometimes be distinguished by the orange color of the housing. Unplug and remove the relay, and place it in a safe location. With the fuel pump relay removed, start the engine and operate it until it stalls. Crank the engine for 10 seconds after it stalls to remove any residual pressure.


WARNING
Fuel lines are under about 43.5-72.5 psi (3-5 bar) of pressure. Manufacturer does not provide a specific pressure relieving procedure, but instructs that any fuel system disconnect will spill fuel, so be prepared to catch and clean up any spilled fuel.


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Fuel Filter

Removal & Installation


  1. Before servicing the vehicle, refer to the Precautions section.
  2. Properly relieve the fuel system pressure.
  3. Remove or disconnect the following:

    Negative battery cable
    Fuel pressure regulator and seal the fuel line before and after the filter with special tool 13-3-010
    Clips and fuel line from the filter
    Fuel filter


To install:



New fuel filter
Fuel lines onto the correct fittings. Tighten the fuel line clamps until tight, but not to the point where the fuel lines become excessively pinched or damaged, then tighten the mounting bracket until snug.
Negative battery cable and cycle the ignitionONOFF

  1. Start the vehicle and check for leaks, repair if necessary.
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Fuel Level Sending Unit

Removal & Installation


There are fuel level sending units in the right and left sides. The procedure is identical for both sides.

  1. Drain the fuel from the fuel tank through the filler hose.
  2. Remove the rear bench seat.
  3. Detach the rubber plug above the sensor and fold back the rubber mat.
  4. Remove the screws and fold back the metal cover.
  5. Detach the electrical connector.
  6. Loosen the hose clamps and remove the hoses.

    Click image to see an enlarged view

    Fig. Detach the electrical connector and remove the hose clamps (1 & 2) to remove the fuel hoses

  7. Use Special Tool 16-1-020 to remove the screw cap.

    Click image to see an enlarged view

    Fig. Use Special Tool 16-01-020 to remove the fuel screw cap

  8. Carefully raise the fuel level sensor until the sensor flange projects out of the sealing area of tank opening.
    WARNING
    Do not pull excessively on the connecting piece of fuel supply hose.

  9. Carefully raise the fuel level sending unit and expose the spiral hose.
  10. Remove the fuel level sending unit with the pump assembly from the fuel tank.

    Click image to see an enlarged view

    Fig. Remove the fuel level sending unit (1) to expose the spiral hose (2)


To install:

  1. Replace the gasket on the fuel level sending unit.
  2. Fit the rubber seal over the fuel level sending unit flange.
  3. Before pressing the sending unit into the tank opening, detach the rubber seal from the flange and then insert into the tank opening.
  4. Press the fuel level sending unit into the tank opening.
  5. The remainder of the installation is the reverse order of removal.

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Fuel System Service Precautions


Safety is the most important factor when performing not only fuel system maintenance but also any type of maintenance. Failure to conduct maintenance and repairs in a safe manner may result in serious personal injury or death. Maintenance and testing of the vehicle's fuel system components can be accomplished safely and effectively by adhering to the following rules and guidelines.

  1. To avoid the possibility of fire and personal injury, always disconnect the negative battery cable unless the repair or test procedure requires that battery voltage be applied.
  2. Always relieve the fuel system pressure prior to disconnecting any fuel system component (injector, fuel rail, pressure regulator, etc.), fitting or fuel line connection. Exercise extreme caution whenever relieving fuel system pressure, to avoid exposing skin, face and eyes to fuel spray. Fuel under pressure may penetrate the skin or any part of the body that it contacts.
  3. Always place a shop towel or cloth around the fitting or connection prior to loosening to absorb any excess fuel due to spillage. Ensure that all fuel spillage (should it occur) is quickly removed from engine surfaces. Ensure that all fuel soaked cloths or towels are deposited into a suitable waste container.
  4. Always keep a dry chemical (Class B) fire extinguisher near the work area.
  5. Do not allow fuel spray or fuel vapors to come into contact with a spark or open flame.
  6. Always use a back-up wrench when loosening and tightening fuel line connection fittings. This will prevent unnecessary stress and torsion to fuel line piping. Always follow the proper torque specifications.
  7. Always replace worn fuel fitting O-rings with new. Do not substitute fuel hose or equivalent where fuel pipe is installed.
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Fuel Tank

Removal & Installation


  1. Drain the any remaining fuel from the tank through the filler hose.
  2. Remove the rear bench seat.
  3. Remove the rubber plugs covering the access holes.
  4. Fold back the rubber mat, remove the screws and fold back the metal covers.
  5. On both sides, disconnect the electrical connectors from the fuel level sensors and detach the tank vent lines.
  6. Raise and safely secure the vehicle.
  7. Remove the driveshaft.
  8. Remove the fuel tank underbody protection.
  9. Remove the fuel filter.
  10. Remove the rear right wheel, then remove the wheel well trim.
  11. Matchmark all of the fill, vent and overflow hoses of the fuel tank, and then disconnect.
  12. Support the fuel tank with a suitable jack.
  13. Remove the mounting bolts for the tank straps. Begin with the right, left and then remove the center support last.
  14. Slowly lower the fuel tank assembly. Remove the line bundle from the wheel well and remove the tank assembly from the vehicle.
  15. Installation is the reverse order of removal.
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