GM Full Size Vans 1987-1997 Repair Guide

Electric Fuel Pump

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See Figure 1

All Chevrolet/GMC fuel-injected vehicles are equipped with an electric fuel pump. For a fuel injection system to work properly, the pump must develop pressures well above those of a mechanical fuel pump. This high pressure is maintained within the lines even when the engine is off. Extreme caution must be used to safely release the pressurized fuel before any work is begun.


CAUTION
Always relieve the fuel pressure within the system before any work is begun on any fuel component. Failure to safely relieve the pressure may result in fire and/or serious injury.



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Fig. Fig. 1: Exploded view of the fuel supply system

REMOVAL & INSTALLATION



Single Tank

See Figures 2, 3 and 4

  1. Disconnect the negative battery cable.
  2.  
  3. Relieve the fuel system pressure. Refer to the fuel system relief procedure in this section.
  4.  
  5. Raise the vehicle and support it safely with jackstands.
  6.  
  7. Drain the fuel system and remove the fuel tank. Refer to the fuel tank removal procedure in this section.
  8.  
  9. Remove the fuel sender assembly turning it counterclockwise using tool J-36608 or its equivalent.
  10.  
  11. Remove the assembly from the tank.
  12.  
  13. Pull the pump up into the attaching hose while pulling outward from the bottom support. Do not damage the rubber insulator or the strainer.
  14.  
  15. Inspect the fuel pump attaching hose and the rubber sound insulation for signs of deterioration.
  16.  
  17. Inspect the strainer for blockage and damage.
  18.  



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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

To install:
  1. Install the fuel pump assembly into the attaching hose.
  2.  

Be careful not to bend or fold over the fuel strainer when installing the fuel sender as this will restrict fuel flow.

  1. Install the fuel sender into the fuel tank. Insert a new O-ring seal.
  2.  
  3. Install the camlock assembly turning it clockwise to lock it.
  4.  
  5. Install the fuel tank. Refer to the fuel tank installation procedure in this section.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Turn the ignition switch ON for 2 seconds then turn the switch OFF for 10 seconds. Again, turn the ignition switch ON and check for leaks.
  10.  

Dual Tanks
  1. Disconnect the negative battery cable.
  2.  
  3. Loosen the filler cap(s) to relieve fuel tank pressure.
  4.  
  5. Disconnect the fuel pipes from the pump.
  6.  
  7. Slide the pump out of the bracket.
  8.  

To install:
  1. Install new fuel pipe O-rings.
  2.  
  3. Position the pump in the pump bracket.
  4.  
  5. Connect the fuel feed pipe and suction pipe to the fuel pump.
  6.  
  7. Using a backup wrench to stop the fuel pump from turning, tighten the fittings to 22 ft. lbs. (30 Nm).
  8.  
  9. Engage the electrical connector.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Turn the ignition switch ON for 2 seconds then turn the switch OFF for 10 seconds. Again, turn the ignition switch ON and check for leaks.
  14.  

 
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