GM Prizm/Nova 1985-1993 Repair Guide

Electric Fuel Pump

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REMOVAL & INSTALLATION



The electric fuel pump used on fuel injected Nova and Prizm cars is contained within the fuel tank. On 1988-92 models it cannot be removed without removing the tank from the car.

Before removing fuel system parts, clean them with a spray-type engine cleaner. Follow the instructions on the cleaner. Do not soak fuel system parts in liquid cleaning solvent.


CAUTION
The fuel injection system is under pressure. Refer to the procedure above and release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. Have a Class B-C (dry powder) fire extinguisher within arm's reach at all times.

1988-92

See Figures 1 and 2

  1. Release the fuel system pressure as outlined earlier.
  2.  
  3. Using a siphon or pump, drain the fuel from the tank and store it in a proper metal container with a tight cap.
  4.  
  5. Remove the rear seat cushion to gain access to the electrical wiring.
  6.  
  7. Disconnect the fuel pump and sending unit wiring at the connector.
  8.  
  9. Raise the vehicle and safely support it on jackstands.
  10.  
  11. Loosen the clamp and remove the filler neck and overflow pipe from the tank.
  12.  
  13. Remove the supply hose from the tank. Wrap a rag around the fitting to collect escaping fuel. Disconnect the breather hose from the tank, again using a rag to control spillage.
  14.  
  15. Cover or plug the end of each disconnected line to keep dirt out and fuel in.
  16.  
  17. Support the fuel tank with a floor jack or transmission jack. Use a broad piece of wood to distribute the load. Be careful not to deform the bottom of the tank.
  18.  
  19. Remove the fuel tank support strap bolts.
  20.  
  21. Swing the straps away from the tank and lower the jack. Balance the tank with your other hand or have a helper assist you. The tank is bulky and may have some fuel left in it. If its balance changes suddenly, the tank may fall.
  22.  
  23. Remove the fuel filler pipe extension, the breather pipe assembly and the sending unit assembly. Keep these items in a clean, protected area away from the car.
  24.  
  25. To remove the electric fuel pump:
    1. Disconnect the 2 pump-to-harness wires.
    2.  
    3. Loosen the pump outlet hose clamp at the bracket pipe.
    4.  
    5. Remove the pump from the bracket and the outlet hose from the bracket pipe.
    6.  
    7. Separate the outlet hose and the filter from the pump.
    8.  

  26.  
  27. While the tank is out and disassembled, inspect it for any signs of rust, leakage or metal damage. If any problem is found, replace the tank. Clean the inside of the tank with water and a light detergent and rinse the tank thoroughly several times.
  28.  
  29. Inspect all of the lines, hoses and fittings for any sign of corrosion, wear or damage to the surfaces. Check the pump outlet hose and the filter for restrictions.
  30.  

To install:
  1. When reassembling, ALWAYS replace the sealing gaskets with new ones. Also replace any rubber parts showing any sign of deterioration.
  2.  
  3. Assemble the outlet hose and filter onto the pump; then attach the pump to the bracket.
  4.  
  5. Connect the outlet hose clamp to the bracket pipe and connect the pump wiring to the harness wire.
  6.  
  7. Install the fuel pump and bracket assembly onto the tank.
  8.  
  9. Install the sending unit assembly.
  10.  
  11. Connect the breather pipe assembly and the filler pipe extension.
  12.  

Tighten the breather pipe screw to 17 inch lbs. and all other attaching screws to 30 inch lbs.

  1. Place the fuel tank on the jack and elevate it into place within the car. Attach the straps and install the strap bolts, tightening them to 29 ft. lbs.
  2.  
  3. Connect the breather hose to the tank pipe, the return hose to the tank pipe and the supply hose to its tank pipe. tighten the supply hose fitting to 21 ft. lbs.
  4.  
  5. Connect the filler neck and overflow pipe to the tank. Make sure the clamps are properly seated and secure.
  6.  
  7. Lower the vehicle to the ground.
  8.  
  9. Connect the pump and sending unit electrical connectors to the harness.
  10.  
  11. Install the rear seat cushion.
  12.  
  13. Using a funnel, pour the fuel that was drained from its container into the fuel filler.
  14.  
  15. Install the fuel filler cap.
  16.  
  17. Start the engine and check carefully for any sign of leakage around the tank and lines.
  18.  



Click image to see an enlarged view

Fig. Fig. 1: Fuel tank components - 1988 VIN Code 5 engine (Nova)



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Fig. Fig. 2: Fuel tank components - 1989-92

1993

See Figures 3, 4 and 5

  1. Release the fuel system pressure as outlined earlier.
  2.  
  3. Using a siphon or pump, drain the fuel from the tank and store it in a proper metal container with a tight cap.
  4.  
  5. Remove the rear seat cushion as outlined in Routine Maintenance 0 to gain access to the service hole.
  6.  
  7. Remove the 4 screws and remove the service hole cover.
  8.  
  9. Disconnect the fuel pump and sending unit wiring at the connector.
  10.  
  11. Remove the 1 nut and disconnect the fuel feed hose from the sender assembly.
  12.  
  13. Remove the 1 clamp and disconnect the fuel return hose from the sender assembly.
  14.  
  15. Remove the 8 bolts and remove the fuel sender assembly from the fuel tank.
  16.  
  17. Remove the fuel pump from the fuel pump bracket by pulling off the lower side of the fuel pump from the bracket.
  18.  
  19. Disconnect the fuel pump electrical connector.
  20.  
  21. Remove the rubber cushion from the fuel pump.
  22.  
  23. Remove the 1 clamp and disconnect the fuel pump strainer from the pump.
  24.  

To install:
  1. Install the 1 clamp and connect the fuel pump strainer to the pump.
  2.  
  3. Install the rubber cushion to the fuel pump.
  4.  
  5. Connect the fuel pump electrical connector.
  6.  
  7. Install the fuel pump to the fuel pump bracket.
  8.  
  9. Install the 8 bolts and install the fuel sender assembly to the fuel tank. Tighten the bolts to 89 inch lbs. (10 Nm).
  10.  
  11. Install the 1 clamp and connect the fuel return hose to the sender assembly.
  12.  
  13. Install the 1 nut and connect the fuel feed hose to the sender assembly. Tighten the nut to 15 ft. lbs. (20 Nm).
  14.  
  15. Connect the fuel pump electrical connector.
  16.  
  17. Install the 4 screws and install the service hole cover.
  18.  
  19. Install the rear seat cushion as outlined in Routine Maintenance 0 .
  20.  
  21. Refill the tank.
  22.  
  23. Connect the negative battery cable.
  24.  



Click image to see an enlarged view

Fig. Fig. 3: Fuel tank components - 1993



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Fig. Fig. 4: Removing the floor service hole cover - 1993



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Fig. Fig. 5: Removing the fuel pump and strainer - 1993

TESTING



1988

See Figure 6

Since the fuel pump is concealed within the tank, it is difficult to test directly at the pump. It is possible to test the pump from under the hood, listening for pump function and feeling the fuel delivery lines for the build-up of pressure.

  1. Turn the ignition switch ON, but do not start the motor.
  2.  
  3. Using a jumper wire, short both terminals of the fuel pump check connector. The check connector is located under the hood near the wiper motor. Connect the terminals labeled FP and +B .
  4.  



Click image to see an enlarged view

Fig. Fig. 6: Checking the electric fuel pump at the check connector

  1. Check that there is pressure in the hose running to the delivery pipe. You should hear fuel pressure noise and possibly hear the pump at the rear of the car.
  2.  
  3. Remove the jumper wire.
  4.  
  5. Turn the ignition to OFF. If the fuel pump failed to function, it may indicate a faulty pump, but before removing the tank and pump, check the following items within the pump system:
    1. the fusible link
    2.  
    3. fuses (EFI/15 amp and IGN/7.5 amp)
    4.  
    5. fuel injection main relay
    6.  
    7. fuel pump circuit opening relay
    8.  
    9. all wiring connections and grounds.
    10.  

  6.  

1989-93

For fuel pump electrical and pressure test on 1989-93 models, please refer to the Fuel System Diagnostic Charts at the end of this section.

 
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