Nissan 240SX/Altima 1993-1998 Repair Guide

Fuel Injectors

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4 and 5



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Fig. Fig. 1: Label and disconnect the fuel injector electrical harnesses



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Fig. Fig. 2: The fuel injectors are retained in the intake manifold by rubber grommets



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Fig. Fig. 3: The fuel injectors are retained in the fuel rail by a special cap



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Fig. Fig. 4: Two O-rings (arrows) are used to provide a leakproof seal between the injector and the fuel rail



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Fig. Fig. 5: Always replace the fuel injector O-rings when servicing the fuel injectors

  1. Properly relieve the fuel system pressure.
  2.  
  3. Disconnect the throttle cable and, if equipped, cruise control cable, from the throttle body.
  4.  
  5. Remove the throttle cable bracket from the intake manifold.
  6.  
  7. Label and disconnect the fuel injector electrical harnesses.
  8.  
  9. Disconnect and cap the fuel feed and return hoses.
  10.  
  11. Disconnect the vacuum line from the fuel pressure regulator.
  12.  
  13. Remove the fuel rail retaining bolts.
  14.  
  15. Remove the fuel rail and injector assembly from the intake manifold.
  16.  
  17. Remove the injector cap from the fuel rail.
  18.  
  19. Twist the injector slightly and pull it from the fuel rail. Repeat for the other injectors, if necessary.
  20.  

Injectors may be very difficult to remove from the fuel rail. Take care not to damage the injector during removal.

  1. Remove and discard the injector O-rings.
  2.  

To install:
  1. Clean the injector tailpiece and insert the injector(s) into the fuel rail with new O-rings.
  2.  
  3. Install the injector cap on the fuel rail and tighten the screws securely.
  4.  
  5. Position the injector and fuel rail assembly onto the intake manifold.
  6.  
  7. Tighten the fuel rail retaining bolts to 12-1 ft. lbs. (3-6 Nm).
  8.  
  9. Connect the vacuum line to the fuel pressure regulator.
  10.  
  11. Connect the fuel feed and return hoses.
  12.  
  13. Connect the fuel injector electrical harnesses.
  14.  
  15. Install the throttle cable bracket.
  16.  
  17. Connect and adjust the throttle and, if applicable, cruise control cables.
  18.  
  19. Pressurize the fuel system and check for leaks.
  20.  

TESTING



See Figures 6, 7 and 8



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Fig. Fig. 6: A noid light can be attached to the fuel injector harness in order to test for injector pulse



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Fig. Fig. 7: Cross-sectional view of a typical fuel injector



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Fig. Fig. 8: Fuel injector testers can be purchased or perhaps rented

  1. Start the engine.
  2.  
  3. Using a screwdriver or mechanic's stethoscope, lay the tool on the injector.
  4.  
  5. Place your ear against the tool and listen for a clicking sound. This sound is the injector valve opening and closing.
  6.  
  7. If a clicking sound is not heard, stop the engine and disconnect the injector electrical harness.
  8.  
  9. Install a noid light or equivalent injector harness test light on the fuel injector harness.
  10.  
  11. Crank the engine and check for injector signal. If signal is present, the fuel injector may be faulty.
  12.  
  13. If signal is present, check the fuel delivery system for proper fuel pressure.
  14.  

 
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