Pontiac Fiero 1984-1988 Repair Guide

Fuel Pumps

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Fig. Fig. 1 View of the electric fuel pump and sending unit assembly used on Fiero models



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Fig. Fig. 2 A special tool is usually available to remove or install the fuel pump locking cam



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Fig. Fig. 3 A brass drift and a hammer can be used to loosen the fuel pump locking cam



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Fig. Fig. 4 Once the locking cam is released it can be removed to free the fuel pump

The Fiero is equipped with a electric fuel pump and gauge sending unit mounted in the fuel tank. The pump is serviced and a complete unit by removing the fuel tank.

REMOVAL & INSTALLATION

CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

  1. Disconnect the negative (-) battery cable.
  2.  
  3. Relieve the fuel system pressure.
  4.  

Remove the fuel pump fuse from the fuse block located in the passenger compartment. Start the engine and run until the engine stops due to the lack of fuel. Crank the engine for 3 seconds to ensure all pressure is relieved.

  1. Drain all the fuel from the tank using a suction pump.
  2.  
  3. Raise the vehicle and support with jackstands.
  4.  
  5. Disconnect the wiring from the tank.
  6.  
  7. Remove the ground wire retaining screw from under the body.
  8.  
  9. Disconnect all hoses and filler neck from the tank.
  10.  
  11. Support the tank on a jack and remove the retaining strap nuts.
  12.  
  13. Lower the tank enough to disconnect the fuel sending unit wires.
  14.  
  15. Disconnect the fuel line, vapor line and return line.
  16.  
  17. Remove the tank from the vehicle.
  18.  
  19. Remove the fuel gauge/pump retaining ring by turning the cam lock ring counterclockwise using a spanner wrench such as tool J-24187.
  20.  
  21. Remove the gauge unit and the pump.
  22.  

To install:

  1. Inspect the fuel pump attaching hose for any signs of deterioration and replace if necessary. Also, check the rubber sound insulator at the bottom of the pump.
  2.  
  3. Push the fuel pump assembly into the attaching hose.
  4.  
  5. Using a new O-ring seal, install the pump assembly into the tank.
  6.  
  7. Install the cam lock ring over the pump and lock by turning clockwise with a spanner wrench J-24187 or equivalent.
  8.  
  9. Support the tank on a suitable jack.
  10.  
  11. Raise the tank enough to connect all fuel and filler hoses.
  12.  
  13. Connect all electrical wires to the pump and tank.
  14.  
  15. Raise the tank and install the retaining strap nuts. Use new sound reducing pad if they are damaged. Check all connections and wire to ensure proper installation before refilling the tank.
  16.  
  17. Refill the tank with unleaded fuel. Reconnect the negative (-) battery cable.
  18.  
  19. Start the engine and check for fuel leaks and gauge operation.
  20.  

TESTING
2.5L Engine
PRESSURE TEST

CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

  1. Remove the fuel pump fuse from the fuse block located in the passenger compartment. Start the engine and run until the engine stops due to the lack of fuel. Crank the engine for 3 seconds to ensure all pressure is relieved.
  2.  
  3. Remove the air cleaner and plug the thermal vacuum port on the throttle body unit.
  4.  
  5. Remove the steel fuel pipe between the throttle body unit and the fuel filter using a flare nut wrench.
  6.  
  7. Install a fuel pressure gauge No. J-29658 or equivalent between the throttle body and fuel filter.
  8.  
  9. Start the vehicle and observe the reading. The pressure should be at least 9-13 psi. If not check for crimped lines or disconnected electrical connectors.
  10.  
  11. Relieve the fuel pressure and disconnect the pressure gauge.
  12.  
  13. Reinstall the steel fuel pipe to the throttle body and torque to 19-25 ft. lbs. (26-34 Nm).
  14.  
  15. Install the air cleaner assembly and start the engine and check for fuel leaks.
  16.  

VOLUME TEST

CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

  1. Remove the fuel pump fuse from the fuse block located in the passenger compartment. Start the engine and run until the engine stops due to the lack of fuel. Crank the engine for 3 seconds to ensure all pressure is relieved.
  2.  
  3. Disconnect the steel fuel pipe from the fuel filter to throttle body.
  4.  
  5. Connect a hose from the steel filter inlet pipe into a suitable fuel resistant unbreakable container.
  6.  
  7. Turn the ignition key to the ON position. The pump should supply 1 / 2 pint or more in 15 seconds. If the volume is minimum, check for fuel restrictions. If there is no restriction found, check pump pressure as outlined in the "Pressure Test" procedures.
  8.  

2.8L Engine
PRESSURE TEST


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Fig. Fig. 5 Location of the fuel system pressure test/relief valve


CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

  1. Connect a fuel gauge part No. J 34730-1 or equivalent to the fuel pressure valve on the fuel rail assembly. Wrap a towel around the fitting while connecting the gauge to prevent fuel spillage. Install the bleed hose into an approved container and open the valve to bleed the system pressure.
  2.  
  3. Disconnect the steel fuel pipe from the fuel filter to throttle body.
  4.  
  5. Connect a fuel pressure gauge J-34730-1 or equivalent to the filter inlet pipe.
  6.  
  7. With the ignition key in the ON position, the pump should run for about 2 seconds and the fuel pressure should be 40.5-47 psi (280-325 kPa).
  8.  
  9. If pressure is low or zero, check for a restriction or blocked fuel line. Also check for pressure regulator and the pump relay.
  10.  
  11. Relieve the fuel pressure and disconnect the pressure gauge.
  12.  
  13. Reinstall the steel fuel pipe to the throttle body and torque to 19-25 ft. lbs. (26-34 Nm).
  14.  

 
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