Mazda Trucks 1994-1998 Repair Guide

Fuel Pump

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REMOVAL & INSTALLATION



Navajo and B Series Pick-up Models

See Figures 1, 2 and 3

To gain access to the fuel pump, it is necessary to remove the fuel tank.

  1. Depressurize the fuel system and remove the fuel tank from the vehicle.
  2.  
  3. Remove any dirt that has accumulated around the fuel pump attaching flange, to prevent it from entering the tank during service.
  4.  
  5. Turn the fuel pump locking ring counterclockwise using a locking ring removal tool and remove the locking ring.
  6.  
  7. Remove the fuel pump and bracket assembly.
  8.  
  9. Remove the seal gasket and discard it.
  10.  

To install:
  1. Put a light coating of heavy grease on a new seal ring to hold it in place during assembly. Install it in fuel tank ring groove.
  2.  



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Fig. Fig. 1: Fuel pump and sending unit used on the B Series Pick-up regular cab



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Fig. Fig. 2: Fuel pump and sending unit used on the B Series Cab Plus Pick-up



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Fig. Fig. 3: Fuel pump and sending unit used on the Navajo

  1. Insert the fuel pump assembly into the fuel tank, then secure it in place with the locking ring. Tighten the ring until secure.
  2.  
  3. Install the tank in the vehicle.
  4.  
  5. Install a minimum of 10 gallons of fuel and check for leaks.
  6.  
  7. Install a pressure gauge on the throttle body valve and turn the ignition ON for 3 seconds. Turn the key OFF , then repeat the key cycle five to ten times until the pressure gauge shows at least 30 psi. Reinspect for leaks at the fittings.
  8.  
  9. Remove the pressure gauge. Start the engine and check for fuel leaks.
  10.  

MPV Models

See Figures 4 and 5

  1. Relieve the fuel system pressure and disconnect the negative battery cable.
  2.  
  3. Remove the rear seat and lift up the rear floormat. Remove the fuel pump cover.
  4.  
  5. Disconnect the sending unit/fuel pump assembly electrical connector and the fuel lines.
  6.  
  7. Remove any dirt that has accumulated around the sending unit/fuel pump assembly so it will not enter the fuel tank during removal and installation.
  8.  
  9. Remove the attaching screws and remove the sending unit/fuel pump assembly.
  10.  
  11. If necessary, disconnect the electrical connectors and the fuel hose and remove the pump from the sending unit assembly.
  12.  
  13. Installation is the reverse of the removal procedure. Be sure to install a new seal rubber gasket.
  14.  



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Fig. Fig. 4: Remove the rear seat and floormat to service the fuel pump



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Fig. Fig. 5: Removing the fuel pump assembly

TESTING



Navajo and B Series Pick-up Models

See Figures 6, 7, 8 and 9


CAUTION
Fuel pressure must be relieved before attempting to disconnect any fuel lines.

The diagnostic pressure valve (Schrader valve) is located on the fuel supply manifold (rail). This valve provides a convenient point for service personnel to monitor fuel pressure, release the system pressure prior to maintenance, and to bleed out air which may become trapped in the system during pressure replacement. A pressure gauge with an adapter is required to perform pressure tests.



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Fig. Fig. 6: Fuel pressure can be checked using an inexpensive pressure/vacuum gauge

If the pressure tap is not installed or an adapter is not available, use a T-fitting to install the pressure gauge between the fuel filter line and the throttle body fuel inlet or fuel rail.

To test the fuel pump, follow the accompanying diagnostic charts. Testing fuel pressure requires the use of a special pressure gauge (Ford Tool T80L-9974-B, Rotunda Fuel Pressure Testing Kit 014-00447, or equivalent) that attaches to the diagnostic pressure tap fitting. To perform the fuel system test a scan tool is necessary to access the different test modes.

Depressurize the fuel system before disconnecting any lines.



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Fig. Fig. 7: Fuel pressure test chart-part 1



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Fig. Fig. 8: Fuel pressure test chart-part 2



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Fig. Fig. 9: Fuel pressure test chart-part 3

MPV Models

See Figures 10 and 11

  1. Relieve the fuel system pressure and disconnect the negative battery cable.
  2.  
  3. Disconnect the fuel line from the fuel filter outlet. Connect a fuel pressure gauge to the fuel filter outlet.
  4.  
  5. Connect the negative battery cable. Connect the data link connector terminals F/P and GND (Ground) with a jumper wire.
  6.  



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Fig. Fig. 10: Install a fuel pressure gauge to the outlet of the fuel filter



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Fig. Fig. 11: Connect a jumper wire between the F/P and GND terminals of the data link connector

  1. Turn the ignition switch ON to operate the fuel pump and check the fuel pressure. It should be 64-92 psi.
  2.  
  3. If the fuel pressure is not as specified, replace the fuel pump.
  4.  
  5. Turn the ignition switch OFF and disconnect the negative battery cable. Remove the jumper wire from the test connector.
  6.  
  7. Remove the fuel pressure gauge and reconnect the fuel line to the fuel filter outlet.
  8.  
  9. Connect the negative battery cable.
  10.  

 
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