Mazda Trucks 1987-1993 Repair Guide

Fuel Pump

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REMOVAL & INSTALLATION



The fuel pump is located inside the fuel tank, attached to the tank sending unit assembly.

Pickup

See Figure 1

  1. Relieve the fuel system pressure and disconnect the negative battery cable.
  2.  
  3. Remove the fuel tank.
  4.  


CAUTION
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.

  1. 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.
  2.  
  3. Remove the attaching screws and remove the sending unit/fuel pump assembly.
  4.  



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Fig. Fig. 1: Exploded view of the fuel pump/sending unit assembly

  1. If necessary, disconnect the electrical connectors and the fuel hose and remove the pump from the sending unit assembly.
  2.  
  3. Installation is the reverse of the removal procedure. Be sure to install a new seal rubber gasket.
  4.  

MPV

See Figures 2, 3 and 4

  1. Relieve the fuel system pressure and disconnect the negative battery cable.
  2.  


CAUTION
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.

  1. Remove the rear seat and lift up the rear floormat. Remove the fuel pump cover.
  2.  
  3. Disconnect the sending unit/fuel pump assembly electrical connector and the fuel lines.
  4.  
  5. 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.
  6.  



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Fig. Fig. 2: Remove the rear seat and floormat to service the fuel pump



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Fig. Fig. 3: Removing the fuel pump assembly



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Fig. Fig. 4: Exploded view of the fuel pump/sending unit assembly

  1. Remove the attaching screws and remove the sending unit/fuel pump assembly.
  2.  
  3. If necessary, disconnect the electrical connectors and the fuel hose and remove the pump from the sending unit assembly.
  4.  
  5. Installation is the reverse of the removal procedure. Be sure to install a new seal rubber gasket.
  6.  

Navajo

See Figure 5

  1. Disconnect the negative battery cable and relieve the fuel system pressure.
  2.  
  3. Raise and safely support the vehicle.
  4.  


CAUTION
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.

  1. Remove the fuel tank.
  2.  
  3. Remove any dirt that has accumulated around the fuel pump attaching flange so it will not enter the fuel tank during removal and installation.
  4.  


CAUTION
If utilizing a hammer and drift (punch) tool to loosen or tighten a fuel pump lock ring, be sure that it is a brass drift. A metal, non-brass drift will most likely produce a spark when struck with or against metal, which can result a fire or explosion.

  1. Turn the fuel pump locking ring counterclockwise using a hammer and brass drift or a spanner tool and ratchet. Remove the locking ring.
  2.  
  3. Remove the fuel pump and discard the seal ring. Separate the fuel pump from the sending unit, if required.
  4.  



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Fig. Fig. 5: Fuel pump/sending unit assembly

To install:
  1. Clean the fuel pump mounting flange and tank mounting surface and seal ring groove.
  2.  
  3. Apply a light coating of Molybdenum grease on a new seal ring and install it in the groove.
  4.  
  5. Install the fuel pump to the sending unit, if removed. Install the fuel pump assembly in the tank, making sure the locating keys are in the keyways and the seal ring is in place.
  6.  
  7. Hold the fuel pump assembly and the seal ring in place and install the locking ring. Rotate the ring clockwise using a suitable tool. If using a hammer and brass drift, carefully tap the ring until it has achieved a tight seal. If using an adjustable spanner tool, attach a torque wrench to the spanner and tighten the locking ring to 40-45 ft. lbs. (54-61 Nm).
  8.  
  9. Install the fuel tank in the vehicle.
  10.  
  11. Lower the vehicle and fill the fuel tank with at least 10 gallons of fuel. Connect the negative battery cable. Turn the ignition key to RUN for 3 seconds repeatedly, 5-10 times, to pressurize the system. Check for leaks.
  12.  
  13. Start the engine and check for leaks.
  14.  

TESTING



Pickup and MPV

See Figures 6, 7 and 8

  1. Relieve the fuel system pressure and disconnect the negative battery cable.
  2.  



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Fig. Fig. 6: Connect the terminals of the yellow 2-pin test connector with a jumper wire-Pickups



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Fig. Fig. 7: Connect the terminals of the yellow 2-pin test connector with a jumper wire-MPV with 3.0L engine



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Fig. Fig. 8: Connect the terminals of the yellow 2-pin test connector with a jumper wire-MPV with 2.6L engine

  1. Disconnect the fuel line from the fuel filter outlet. Connect a fuel pressure gauge to the fuel filter outlet.
  2.  
  3. Connect the negative battery cable. Connect the terminals of the yellow 2-pin test connector with a jumper wire.
  4.  
  5. Turn the ignition switch ON to operate the fuel pump and check the fuel pressure. It should be 64-85 psi.
  6.  
  7. If the fuel pressure is not as specified, replace the fuel pump.
  8.  
  9. Turn the ignition switch OFF and disconnect the negative battery cable. Remove the jumper wire from the test connector.
  10.  
  11. Remove the fuel pressure gauge and reconnect the fuel line to the fuel filter outlet.
  12.  
  13. Connect the negative battery cable.
  14.  

Navajo

See Figures 9 and 10

  1. Make sure there is an adequate fuel supply.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Turn the ignition key OFF .
  6.  
  7. Connect a suitable fuel pressure gauge to the Schrader valve on the fuel rail.
  8.  
  9. Install a test lead to the FP terminal on the VIP test connector.
  10.  
  11. Turn the ignition key to the RUN position, then ground the test lead to run the fuel pump.
  12.  
  13. Observe the fuel pressure reading on the pressure gauge. The fuel pressure should be 35-45 psi.
  14.  
  15. Relieve the fuel system pressure and turn the ignition key OFF . Remove the fuel pressure gauge and the test lead.
  16.  



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Fig. Fig. 9: The fuel pressure relief valve (A) is located on the fuel supply manifold



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Fig. Fig. 10: Fuel pressure can be checked and/or released using an inexpensive pressure/vacuum gauge

 
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