Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Fuel Pumps

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REMOVAL & INSTALLATION



Transfer Pump
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the rear seat and the access cover.
  4.  
  5. Disconnect the wiring and hoses, then unscrew the lock ring.
  6.  
  7. Carefully lift out the pump and gauge sending unit assembly.
  8.  
  9. Installation is the reverse of removal. When installing the assembly, use a new seal.
  10.  

Main Pump

See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Raise and safely support the rear of the vehicle on jackstands.
  6.  
  7. Disconnect the wiring from the pump. Clean any dirt away from the fuel line fitting.
  8.  
  9. Use locking pliers to pinch off the fuel line from the transfer pump to the main pump. If the fuel line is metal, remove the rear seat and access panel, then disconnect the line at the transfer pump.
  10.  



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Fig. Fig. 1: Fuel pump, reservoir and filter assembly used on the Digifant system; the transfer pump is inside the fuel tank

  1. Place a pan under the pump and disconnect the fuel line fitting from the pump.
  2.  
  3. Remove the retaining ring screws and slide the pump out of the reservoir.
  4.  

To install:
  1. Moisten the pump O-ring with a little fuel, then slide it into the reservoir. Install the retaining ring screws.
  2.  
  3. When connecting the fittings, use new copper washers and torque the fittings to 15 ft. lbs. (20 Nm).
  4.  
  5. Connect the battery cable.
  6.  

TESTING



Operating Test
  1. Have an assistant operate the starter. Listen near the fuel pump location to determine if the pump is running.
  2.  
  3. If the pump is not running, check the wiring and the fuse on the front of the fuel pump relay.
  4.  
  5. If the fuse is good, replace the fuel pump relay.
  6.  
  7. If the fuel pump still does not operate, and you're sure there are no loose connections in the wiring, the fuel pump is faulty and must be replaced.
  8.  

Pressure and Delivery Test
  1. Connect tool VW 1318 or an equivalent fuel pressure gauge to the fuel line T-piece. If equipped, the fuel shut-off lever on the gauge must be in a closed position.
  2.  
  3. Locate and remove the fuel pump relay. Install tool US 4480/3 in the fuel pump relay socket. This is essentially a jumper wire with a switch used to turn on the fuel pump. The fuel pump will run any time the switch is ON.
  4.  
  5. Run fuel pump and observe the pressure reading. It must be a minimum of 36 psi. Shut the fuel pump OFF, then relieve the fuel system pressure.
  6.  
  7. Be sure that the fuel tank is at least half full of fuel. Disconnect fuel return line at pressure regulator.
  8.  
  9. Disconnect the fuel return line at the pressure regulator, then plug it with the cap from the CO measuring tube or any other suitable plug.
  10.  
  11. Attach a 4 ft. (123cm) length of fuel line to the return port of the pressure regulator. Place other end of the fuel line into a 1 liter measuring container.
  12.  
  13. Run the fuel pump for exactly 30 seconds. Delivery quantity should be at least 300cc.
  14.  
  15. If delivery quantity is not within specification, check the fuel flow from the tank before and after the fuel filters.
  16.  

 
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