Buick Regal 1997-2000

Fuel Pump

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Removal & Installation



The fuel pump is located inside the fuel tank. It is part of a so-called 'fuel pump module' or 'fuel sender assembly' which includes the fuel pump, the fuel tank gauge sending unit, the fuel pump strainer and related components. These fuel pump module assemblies are expensive. Be sure of the diagnosis before attempting this procedure to replace a fuel pump.

On some vehicles covered by this manual, the fuel sender assembly can be accessed through a removable panel on the trunk floor. On others, the fuel tank must be removed. The spare tire and trunk carpet have to be removed to expose the trunk floor access panel to see which is the proper procedure to use on your vehicle.

With Trunk Access Panel

CAUTION
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion. Wear safety glasses to protect the eyes from fuel splash.


NOTE
Always replace the fuel sender O-rings when reinstalling the fuel sender assembly. Note that the module assembly is spring loaded and it will spring-up when the retaining snapring is removed.


WARNING
When removing the modular fuel sender assembly from the fuel tank, the reservoir bucket on the fuel sender assembly is full of fuel. The sender assembly must be tipped slightly during removal to avoid damage to the float. Place any remaining fuel into an approved container once the sender assembly is removed from the fuel tank.



Click image to see an enlarged view

Fig. Some vehicles have access panels built into the trunk floor so the fuel pump/sender module can be removed without having to remove the fuel tank

  1. Relieve the fuel system pressure using the procedures found in this section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Drain the fuel tank to no more than 1 / 4 of a tank full.
  6.  
  7. Remove the spare tire cover, the jack and the spare tire.
  8.  
  9. Remove the trunk liner.
  10.  
  11. Remove the seven access panel retaining nuts, then lift off the panel.
  12.  
  13. Detach the fuel pump/sender electrical connector.
  14.  
  15. Clean the fuel pipes and the fuel sender assembly to prevent possible fuel contamination during removal.
  16.  
  17. Remove the quick-connect fittings at the fuel sender assembly. Information on servicing these fittings is found earlier in this section.
  18.  
  19. Remove the fuel sender assembly retaining snapring. Expect the sender to spring-up when the snapring is removed.
  20.  


CAUTION
Do not handle the fuel sender assembly by the fuel pipes. The pipe joints are very fragile. The amount of leverage generated by handling the fuel pipes could damage the joints.

  1. Carefully remove the sender assembly. Inspect and clean the O-ring sealing surfaces.
  2.  

To install:


NOTE
Care should be taken not to fold over or twist the fuel pump strainer when installing the fuel sender assembly as this will restrict fuel flow. Also, make sure that the fuel pump strainer does not block the full travel of the fuel gauge float arm.

  1. Position the new fuel sender assembly O-ring on the tank and carefully install the sender assembly into the fuel tank.
  2.  
  3. Install the retaining snapring. Be sure the snapring is fully seated within the tab slots on the fuel tank.
  4.  
  5. Assemble the electrical connector to the sender assembly.
  6.  
  7. Install the quick-connect fittings to the sender assembly.
  8.  
  9. Connect the negative battery cable and install the fuel filler cap.
  10.  
  11. Inspect for leaks using the following procedure:
    1. Turn the ignition switch to the ON position for 2 seconds.
    2.  
    3. Turn the ignition switch to the ON position for 10 seconds.
    4.  
    5. Turn the ignition switch to the ON position again.
    6.  
    7. Check for fuel leaks.
    8.  

  12.  
  13. When satisfied with the fuel sender installation and that connections are secure, install the access cover and the retaining nuts. Snug down the nuts to 96 inch lbs. (10 Nm).
  14.  
  15. Install the trunk liner, spare tire, jack and tire cover.
  16.  

Without Trunk Access Panel

CAUTION
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion. Wear safety glasses to protect the eyes from fuel splash.


NOTE
On Oldsmobile models, a special tool, J 35731 Fuel Sender Spanner Wrench is required to disengage the fuel sender assembly. On Chevrolet models, a snapring is usually used to retain the spring-loaded module assembly which will spring-up when the retaining snapring is removed. Always replace the fuel sender O-ring when reinstalling the fuel sender assembly.


WARNING
When removing the modular fuel sender assembly from the fuel tank, the reservoir bucket on the fuel sender assembly is full of fuel. The sender assembly must be tipped slightly during removal to avoid damage to the float. Place any remaining fuel into an approved container once the sender assembly is removed from the fuel tank.



Click image to see an enlarged view

Fig. On applications with extra-long fuel pipes, the fuel tank has to be removed to service the fuel sender module

  1. Relieve the fuel system pressure using the procedures found in this section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Drain the fuel tank into a suitable container.
  6.  
  7. Raise and safely support the vehicle.
  8.  
  9. Remove the fuel tank using the procedures found in this section. As the tank is being lowered, clean the fuel pipes and the fuel sender assembly to prevent possible fuel contamination. Remove the quick-connect fittings at the fuel sender assembly. Information on servicing these fittings is found in the section. Detach the electrical connector and with an assistant, lower the fuel tank to the floor.
  10.  
  11. On Oldsmobile vehicles use J-35731 Fuel Sender Spanner Wrench, or equivalent, to remove the fuel sender assembly retaining cam (lock ring). Then remove the sender assembly and O-ring. Discard the O-ring.
  12.  
  13. On Chevrolet vehicles, remove the fuel sender assembly retaining snapring. Expect the sender to spring-up when the snapring is removed.
  14.  


CAUTION
Do not handle the fuel sender assembly by the fuel pipes. The joints are very fragile. The amount of leverage generated by handling the fuel pipes could damage the joints. This is especially true of some Oldsmobile application which use long fuel pipes which are easily damaged.

  1. Carefully remove the sender assembly. Inspect and clean the O-ring sealing surfaces.
  2.  

To install:

  1. Care should be taken not to fold over or twist the fuel pump strainer when installing the fuel sender assembly as this will restrict fuel flow. Also, make sure that the fuel pump strainer does not block the full travel of the fuel gauge float arm.
  2.  
  3. Position the new fuel sender assembly O-ring on the tank and carefully install the sender assembly into the fuel tank.
    1. On Oldsmobile applications use a suitable fuel sender spanner wrench, to properly tighten the sender assembly retainer cam.
    2.  
    3. On Chevrolet applications, install the retaining snapring. Be sure the snapring is fully seated within the tab slots on the fuel tank.
    4.  

  4.  
  5. With an assistant, raise the tank and assemble the electrical connector to the sender assembly. Install the quick-connect fittings to the sender assembly. Finish installing the fuel tank using the procedures found in this section. Take care that all insulators and heat shields are in place.
  6.  
  7. Lower the vehicle. Add fuel, connect the negative battery cable and install the fuel filler cap.
  8.  
  9. Inspect for leaks using the following procedure:
    1. Turn the ignition switch to the ON position for 2 seconds.
    2.  
    3. Turn the ignition switch to the OFF position for 10 seconds.
    4.  
    5. Turn the ignition switch to the ON position again.
    6.  
    7. Inspect all areas for fuel leaks.
    8.  

  10.  

Testing



When the ignition switch is first turned ON , the PCM energizes the fuel pump relay which applies power to the fuel pump. The fuel pump relay will remain ON as long as the engine is running or cranking and the PCM is receiving reference pulses. If no reference pulses are present, the PCM de-energizes the fuel pump relay within 2 seconds after the ignition is turned ON or the engine is stopped. The fuel pump delivers fuel to the fuel rail and injectors, then to the fuel pressure regulator. The fuel pressure regulator controls the fuel pressure by allowing excess fuel to be returned to the fuel tank. With the engine stopped, the fuel pump can be turned ON by using the scan tool output controls function.

An intermittent can be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for a poor connection or a damaged harness, Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connections and damaged harness.

The fuel pump relay is located in the underhood electrical center.

  1. A quick-check is to remove the fuel tank cap. Have an assistant listen at the fuel filler opening while you turn the ignition switch to the ON position. Do not crank the engine. Do not start the engine. The fuel pump should run for two seconds and the assistant should be able to hear the pump run briefly. If no noise is heard, there may be a fault in the pump, relay or wiring.
  2.  

Pressure Testing
  1. Locate the fuel pressure test port. It may be necessary to remove the cosmetic/acoustic engine cover to access the test port.
  2.  
  3. Connect a fuel pressure test gauge J-34730-1A, or equivalent, to the fuel pressure connection test port. Wrap a shop cloth around the fuel pressure connection while connecting the fuel pressure hose fitting to avoid spillage. This tool has a bleed hose that should be placed in an approved container to catch the fuel the will be expelled when the valve is opened.
  4.  
  5. Turn the ignition switch to the ON position. The fuel pump should run for two seconds. The pressure on the gauge should read 48-55 psi (333-376 kPa).
  6.  
  7. Start the engine and allow to idle. The fuel pressure should drop about 3-10 psi (21-69 kPa). The idle pressure may vary somewhat, depending on barometric pressure. Look for a big drop in fuel pressure, rather than a specific number.
  8.  
  9. If the fuel pressure drops more than a few pounds when you shout the engine OFF , there may be a problem in the pump coupling, fuel pressure regulator or the injectors.
  10.  
  11. Before attempting to remove or service any fuel system component, it is necessary to relieve the fuel system pressure, as outlined above.
  12.  

 
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