GM Lumina/Grand Prix/Cutlass Supreme/Regal 1988-1996

Electric Fuel Pump

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TESTING



  1. Connect pressure gauge J-34730-1, or equivalent, to 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.  
  3. Turn the ignition ON and check that pump pressure is 24-40 psi. (165-276 kPa)
  4.  
  5. Start the engine and allow it to idle. The fuel pressure should drop to 28-32 psi (193-221 kPa) due to the lower manifold pressure.
  6.  

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, check the operation of the check valve, the pump coupling connection, fuel pressure regulator valve and the injectors. A restricted fuel line or filter may also cause a pressure drip. To check the fuel pump output, restrict the fuel return line and run 12 volts to the pump. The fuel pressure should rise to approximately 75 psi (517 kPa) with the return line restricted.
  2.  
  3. Before attempting to remove or service any fuel system component, it is necessary to relieve the fuel system pressure.
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REMOVAL & INSTALLATION



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the fuel sender, including the fuel pump

  1. Properly relieve the fuel system pressure, as outlined earlier.
  2.  


CAUTION
Fuel injection systems remain under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.

  1. If not already done, disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle with jackstands.
  4.  
  5. Safely drain and remove the fuel tank assembly as outlined later in this section.
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  7. Detach the quick-connects from the fuel sender assembly and remove the fuel lines.
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  9. Using tool J 35731, or an equivalent spanner wrench, remove the fuel sender lockring.
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  11. Lift the sender assembly carefully out of the fuel tank.
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  13. Remove the sender O-ring from the top of the sender and discard.
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WARNING
Do NOT run the fuel pump unless it is submerged in fuel. Running the pump dry will cause serious damage to the fuel pump and may cause the pump to explode due to the oxygen in the air.

  1. Note the position of the fuel pump strainer on the fuel pump and, while supporting the pump assembly in one hand, twist the strainer OFF the pump and discard the strainer.
  2.  
  3. Detach the fuel pump electrical connector.
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  5. Remove the clamp from the fuel line at the top of the pump.
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  7. Hold the fuel sender upside down on a work bench and pull the fuel pump out of the lower mounting bracket. Once the pump is clear of the lower mounting bracket, tilt the pump outward and disconnect the pump from the sender assembly.
  8.  

To install:
  1. Replace any attaching hoses or rubber sound insulators that show signs of deterioration.
  2.  
  3. Install the rubber bumper and insulator on the fuel pump.
  4.  
  5. Hold the fuel sender upside down and install the fuel pump between the fuel pulse dampener and mounting bracket.
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  7. Attach the fuel pump electrical connector.
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  9. Install the retaining clamp on the fuel line.
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  11. Install a new fuel pump strainer on the outer edge of the ferrule until fully seated. The strainer must be facing the same direction as it was before removal.
  12.  
  13. Position a new O-ring on the top of the fuel tank and install the sender assembly.
  14.  
  15. Install the lockring using J-35731, or an equivalent spanner wrench.
  16.  
  17. Install the fuel tank as outlined later in this section.
  18.  
  19. Refill the gas tank.
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  21. Connect the negative battery cable.
  22.  
  23. Turn the ignition switch to the ON position to pressurize the fuel system and check for leaks.
  24.  

 
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