GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Electric Fuel Pump

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TESTING



  1. Properly relieve the fuel system pressure.
  2.  
  3. Remove the air cleaner assembly and plug the THERMAC vacuum port on the TBI unit.
  4.  
  5. Raise and support the rear of the vehicle safely using jackstands.
  6.  
  7. Remove the flexible fuel line between the fuel tank and the fuel filter (located near the tank).
  8.  
  9. Install a fuel pressure gauge, such as J-29658 or equivalent, inline between the fuel tank and fuel filter. If necessary use an adapter or Tee fitting in order to connect the gauge and complete the fuel circuit.
  10.  

A Tee fitting may be fabricated for this purpose. Depending on the fuel gauge being used, short lengths of steel tubing, appropriately sized flare nuts and a flare nut adapter may be used.

  1. Make sure the vehicle is secure, then start the engine.
  2.  
  3. Check to be sure the lines are intact and there are no leaks, then observe the fuel pressure, it should be 9-13 psi (62-90 kPa).
  4.  
  5. Once the test is completed, depressurize the fuel system and remove the gauge.
  6.  
  7. Secure the fuel lines and check for leaks.
  8.  
  9. Remove the plug from the THERMAC vacuum port, then install the air cleaner assembly.
  10.  
  11. Remove the jackstands and carefully lower the rear of the vehicle.
  12.  

REMOVAL & INSTALLATION



See Figures 1 and 2

  1. Properly relieve the fuel system pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise the rear of the vehicle and support safely using jackstands.
  6.  
  7. Drain the fuel tank, then remove it from the vehicle.
  8.  
  9. Using a hammer and a drift punch, carefully drive the lockring (located on top of the fuel tank) for the fuel level sending unit/pump assembly counterclockwise. Lift the assembly from the tank and remove the pump from the fuel lever sending device.
  10.  
  11. Pull the pump up into the attaching hose while pulling it outward away from the bottom support. Be careful not to damage the rubber insulator and strainer during removal. After the pump assembly is clear of the bottom support, pull it out of the rubber connector.
  12.  

To install:
  1. Install the fuel pump attaching hose for any signs of deterioration and replace, as necessary. Also, check the rubber sound insulator at bottom of pump.
  2.  
  3. Push the fuel pump assembly into the attaching hose.
  4.  
  5. Install the fuel level sending unit/pump assembly into the tank using a new O-ring.
  6.  

Special care should be taken when installing the pump assembly to the tank not to fold or twist the fuel strainer or flow will be restricted.

  1. Install the lockring and secure the sending unit/pump assembly by turning the lockring clockwise.
  2.  
  3. Install the fuel tank to the vehicle.
  4.  
  5. Remove the jackstands and carefully lower the vehicle.
  6.  
  7. Connect the negative battery cable, then start the engine and check for leaks.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: Fuel supply system-Throttle Body Injection (TBI) system



Click image to see an enlarged view

Fig. Fig. 2: Example of a common intank fuel pump assembly

 
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