GM Bonneville/Eighty Eight/LeSabre 1986-1999

Electric Fuel Pump

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TESTING



See Figures 1 and 2

  1. Unscrew the cap from the fuel rail pressure valve on the fuel rail. You may have to remove the fuel injector sight shield for access to the valve.
  2.  



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Fig. Fig. 1: Remove the cap (1) from the fuel rail pressure valve (2) on the fuel rail

  1. Connect pressure gauge J-34730-1 or equivalent to the fuel pressure test point on the fuel rail. Wrap a rag around the pressure tap to absorb any leakage that may occur when installing the gauge.
  2.  



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Fig. Fig. 2: Test the fuel system pressure using a suitable gauge attached to the test connection

  1. Turn the ignition ON ; the fuel pump should run for a few seconds. Check the pump pressure for the following specifications:
    1. 1987-93 vehicles, except 1993 VIN K: 41-47 psi (284-323 kPa).
    2.  
    3. 1993 VIN K and 1996-99 vehicles: 48-33 psi (333-376 kPa).
    4.  

  2.  
  3. Start the engine and allow it to idle. The fuel pressure should drop about 3-10 psi (21-69 kPa) due to the lower manifold pressure.
  4.  

The idle pressure will vary somewhat depending on barometric pressure. Check for a drop in pressure indicating regulator control, rather than specific values.

  1. If the fuel pressure drops more than a few pounds when you shut the engine OFF , check the operation of the check valve, the pump coupling connection, fuel pressure regulator valve and the injectors.
  2.  
  3. Before attempting to remove or service any fuel system component, it is necessary to relieve the fuel system pressure.
  4.  

REMOVAL & INSTALLATION



See Figures 3 and 4

The fuel pump is located in the fuel tank. The fuel tank must be removed from the vehicle in order to access the pump.

  1. Properly relieve fuel system pressure.
  2.  
  3. If not already done, disconnect the negative battery cable.
  4.  
  5. Raise and safely support the vehicle.
  6.  
  7. Safely drain and remove the fuel tank assembly, as outlined later in this section.
  8.  
  9. If necessary, detach the quick-connect fittings from the fuel sender assembly and remove the fuel lines.
  10.  
  11. Remove the fuel gauge sender and pump assembly by turning the cam locking ring counterclockwise. It may be necessary to use a spanner wrench, such as tool J-24187, to perform this.
  12.  
  13. Carefully lift the assembly from the fuel tank, then remove the fuel pump from the fuel gauge sender unit.
  14.  
  15. Remove the sender O-ring from the top of the sender and discard.
  16.  
  17. Disconnect the pump wires, hose clamps and the clamp from around the pump body.
  18.  
  19. Pull the pump assembly out of the rubber connectors.
  20.  
  21. Inspect the fuel pump attaching hose for any signs of deterioration, and replace as necessary.
  22.  



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Fig. Fig. 3: Exploded view of the fuel pump and related components - 1987-91 vehicles



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Fig. Fig. 4: Exploded view of the fuel sender and pump - 1993 vehicle shown, later years similar

To install:
  1. Push the fuel pump assembly into the attaching hose. Attach the pump electrical wires and fasten the hose clamps to the attaching hose and around the pump body.
  2.  
  3. Place the fuel tank sender and pump assembly into the fuel tank. Use a new O-ring seal during assembly.
  4.  
  5. Place the cam lock over the assembly, then lock by turning clockwise, using a suitable spanner wrench, if necessary.
  6.  
  7. If removed, attach the fuel sender fuel line quick-connect fittings.
  8.  

When installing the fuel tank, make sure all rubber sound isolators or anti-squeak spacers are replaced in their original locations.

  1. Install the fuel tank, as outlined later in this section.
  2.  
  3. Refill the fuel tank.
  4.  
  5. Connect the negative battery cable.
  6.  
  7. Turn the ignition switch to the ON position to pressurize the fuel system and check for leaks.
  8.  

 
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