Mazda B-Series 1998-06

Fuel Rail (Supply Manifold) & Injectors

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Removal & Installation



  1. Remove the upper intake manifold. Be sure to depressurize the fuel system before disconnecting any fuel lines.
  2.  
  3. Disconnect the fuel supply and return line retaining clips.
  4.  
  5. Detach the vacuum line from the fuel pressure regulator.
  6.  
  7. Disconnect the fuel chassis inlet and outlet fuel hoses from the fuel supply manifold.
  8.  



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Fig. Exploded view of the 2.3L engine fuel supply rail and injectors-2.5L engine similar



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Fig. Exploded view of the 3.0L engine fuel supply rail and injectors



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Fig. Exploded view of the 4.0L engine fuel supply rail and injectors



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Fig. For fuel supply manifold removal, unbolt the upper intake, then disconnect the injector wire harness plugs

  1. Label and disconnect the fuel injector wire harness plugs.
  2.  
  3. On the 2.3L engine, remove the two fuel supply manifold retaining bolts.
  4.  
  5. On the 4.0L engine, remove the six upper intake manifold attaching studs.
  6.  



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Fig. On the 4.0L engine, remove the 6 manifold mounting studs which retain the supply manifold

  1. On all other engines, remove the four fuel supply manifold retaining bolts.
  2.  
  3. Carefully disengage the fuel rail assembly from the fuel injectors by lifting and gently rocking the rail.
  4.  



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Fig. Some models use small retaining clips to secure the injectors in the supply manifold



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Fig. Lift upwards with a rocking motion to disengage the injectors, then remove the supply manifold



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Fig. On the 4.0L engine, remove the old fuel supply manifold gasket and clean the mating surfaces

  1. Remove the fuel injectors from the intake manifold by lifting while gently rocking them from side to side
  2.  



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Fig. Remove the injectors from the engine by gently rocking it while pulling upwards

  1. Place all removed components on a clean surface to prevent contamination by dirt or grease.
  2.  

Never use silicone grease; it will clog the injector. All injectors and the fuel rail must be handled with extreme care to prevent damage to sealing areas and sensitive fuel metering orifices.



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Fig. The injector has O-rings at the nozzle (A) and at the fuel supply manifold (B). Replace any damaged seals

  1. Examine the injector O-rings for deterioration damage, replacing them as needed.
  2.  
  3. Make sure the injector caps are clean and free from contamination or damage.
  4.  

To install:

  1. Lubricate all O-rings with clean engine oil, then install the injectors into the fuel rail using a light twisting/pushing motion.
  2.  
  3. On the 4.0L engine, position a new fuel rail gasket to the lower intake manifold.
  4.  
  5. Carefully install the fuel rail assembly and injectors into the lower intake manifold. Make certain to correctly position the insulators. Push down on the fuel rail to make sure the O-rings are seated.
  6.  
  7. Hold the fuel rail assembly in place and install the retaining bolts finger tight. Then tighten the bolts to specifications.
  8.  
  9. Connect the fuel supply and return lines.
  10.  
  11. Attach the vacuum hose to the fuel pressure regulator.
  12.  
  13. Connect the fuel injector wiring harness at the injectors.
  14.  
  15. Connect the vacuum line to the fuel pressure regulator, if removed.
  16.  
  17. Install the air intake and throttle body assembly.
  18.  
  19. Run the engine and check for fuel leaks.
  20.  

2.3L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:
    WARNING
    Use O-ring seals that are made of special fuel-resistant material. Use of ordinary O-ring seals can cause the fuel system to leak. Do not reuse the O-ring seals.



    Negative battery cable
     
    Upper intake manifold
     
    Fuel injector connectors
     
    Fuel injector harness from the fuel injector supply manifold
     
    Fuel line spring lock
     
    Fuel line
     
    Fuel injection supply manifold
     
    Fuel injector retaining clip
     
    Fuel injector
     

  6.  
  7. Installation is the reverse of removal. Install new O-rings. Lubricate the O-rings with clean engine oil.

    Click image to see an enlarged view

    Fig. Fuel injector-to-fuel rail installation. 1-retaining clip; 2-injector-2.3L engine



    Click image to see an enlarged view

    Fig. Fuel injector O-rings-2.3L engine

  8.  

2.5L & 4.0L OHV Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:

    Negative battery cable
     
    Fuel injection supply manifold
     
    Fuel injectors by gently twisting them
     
    Inspect the O-rings and replace as needed
     

  6.  

To install:

  1. Install or connect the following:

    Fuel injectors
     
    Fuel injector supply manifold
     
    Negative battery cable
     

  2.  
  3. Start the vehicle, check for leaks and repair if necessary.
  4.  

3.0L & 4.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:

    Negative battery cable
     
    Upper intake manifold
     
    Engine control sensor wiring from the fuel injectors
     
    Fuel lines
     
    Fuel injection supply manifold and injectors as an assembly
     
    Vacuum line
     
    Fuel injectors from the supply manifold
     
    Inspect the O-rings and replace them as needed
     

  6.  

To install:

  1. Install or connect the following:

    Fuel injectors
     
    Vacuum line
     
    Fuel injection supply manifold. Torque the bolts to 89 inch lbs. (10 Nm).
     
    Fuel line
     
    Engine control sensor wiring to the fuel injectors
     
    Upper intake manifold
     
    Negative battery cable
     

  2.  
  3. Start the vehicle, check for leaks and repair if necessary.
  4.  

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
    NOTE
    On some vehicles, when the battery cable is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven to relearn its strategy.

  4.  
  5. Properly relieve the fuel system pressure.
  6.  
  7. Remove or disconnect the following:

    Upper intake manifold
     
    Engine control sensor wiring from the fuel injectors
     
    Fuel lines
     
    Fuel injection supply manifold and injectors as an assembly
     
    Vacuum line
     
    Fuel injectors from the supply manifold
     
    Inspect the O-rings and replace them as needed

    Click image to see an enlarged view

    Fig. Fuel injector wiring connectors-3.0L engine



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    Fig. Fuel rail bolts-3.0L engine



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    Fig. Fuel rail and injectors-3.0L engine



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    Fig. Fuel rail and injectors-4.0L engine



    Click image to see an enlarged view

    Fig. Fuel injector O-rings-4.0L engine

     

  8.  

To install:

  1. Install or connect the following:

    Fuel injectors
     
    Vacuum line
     
    Fuel injection supply manifold. Torque the bolts to 89 inch lbs. (10 Nm).
     
    Fuel line
     
    Engine control sensor wiring to the fuel injectors
     
    Upper intake manifold
     
    Negative battery cable
     

  2.  
  3. Start the vehicle, check for leaks and repair if necessary.
  4.  

 
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