GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Fuel Injectors

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REMOVAL & INSTALLATION



1994-97 Models

See Figures 1 through 8



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Fig. Fig. 1: Cross-sectional view of a typical MFI fuel injector



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Fig. Fig. 2: Common accelerator cam splash shield

The bottom feed fuel injectors on the 2.2L MFI engine are installed to the lower intake manifold assembly. For access, the upper intake must first be removed.

Take care when servicing the lower intake and fuel injectors to prevent dirt or contaminants from entering the fuel system. ALL openings in the fuel lines and passages should be capped or plugged while disconnected.

  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Remove the accelerator bracket retaining bolts/nuts, then remove or reposition the bracket.
  4.  
  5. Remove the upper intake manifold assembly. For details, please refer to the intake manifold procedures found in Engine and Engine Rebuilding of this repair guide.
  6.  
  7. Remove the fuel return line bracket nut, then remove the return line retaining bracket and position it away from the pressure regulator.
  8.  
  9. Remove the fuel pressure regulator assembly. For details, please refer to the procedure later in this section.
  10.  

DO NOT attempt to remove the injectors from their bores while lifting upward on the retaining bracket or damage may occur. DO NOT attempt to remove the bracket without first removing the pressure regulator.

  1. Remove the fuel injector retainer bracket attaching screws, then remove the bracket by carefully sliding it off to clear the injector slots.
  2.  
  3. Tag and unplug the injector electrical connectors.
  4.  
  5. Remove the fuel injectors from the lower intake manifold assembly, then remove and discard the old O-rings.
  6.  



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Fig. Fig. 3: Remove the fuel injector retainer bracket attaching screws (arrows)



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Fig. Fig. 4: Remove the bracket by carefully sliding it off to clear the injector slots



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Fig. Fig. 5: Unplug the injector electrical connectors



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Fig. Fig. 6: Remove the fuel injectors from the lower intake manifold assembly



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Fig. Fig. 7: Remove the injector O-rings and discard them



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Fig. Fig. 8: You may need to use a pick to remove the O-rings as the are sometimes hard to get a hold of

To install:

Because each injector is calibrated for a specific flow rate, make sure you only replace fuel injectors using an IDENTICAL part number to the old injectors.

  1. Lubricate the new O-ring seals with clean engine oil, then position them on the injectors.
  2.  
  3. Carefully install the injectors assemblies into the lower manifold sockets, making sure the electrical connectors are facing inward.
  4.  
  5. Position the injector bracket to the retaining slots and regulator are aligned with the bracket slots.
  6.  
  7. Engage the injector electrical connectors as tagged during removal.
  8.  
  9. Install the fuel pressure regulator assembly.
  10.  
  11. Make sure the threads of the injector retainer bracket screws are coated with a suitable threadlocking compound such as Loctite®262 or equivalent, then install and tighten them to 31 inch lbs. (3.5 Nm).
  12.  
  13. Install the upper intake manifold assembly. Please refer to the procedure in Engine and Engine Rebuilding of this repair guide.
  14.  
  15. If not done already, install the accelerator cable bracket. Tighten the retaining nut to 22 ft. lbs. (30 Nm) and the retaining bolts to 18 ft. lbs. (25 Nm).
  16.  
  17. Connect the negative battery cable.
  18.  
  19. Pressurize the fuel system by cycling the ignition (without attempting to start the engine), then check for leaks.
  20.  
  21. If not done already, install the air inlet duct
  22.  

1998-99 Models
  1. Relieve the fuel system pressure and disconnect the negative battery cable.
  2.  
  3. Remove the fuel rail.
  4.  
  5. Remove the fuel injector retaining clip.
  6.  
  7. Remove the injector.
  8.  

Because each injector is calibrated for a specific flow rate, make sure you only replace fuel injectors using an IDENTICAL part number to the old injectors.

To install:

When installing the injector care should be taken not to tear or misalign O-rings.

  1. Lubricate the injector O-ring seals with clean engine oil and install them injector.
  2.  
  3. Install the upper O-ring, lower back-up O-ring and lower O-ring.
  4.  
  5. Attach the fuel injector to the fuel rail.
  6.  
  7. Install the injector retaining clip and install the fuel rail.
  8.  
  9. Connect the negative battery cable.
  10.  
  11. Inspect for leaks as follows:
    1. Turn the switch to the ON position for 2 seconds.
    2.  
    3. Turn the ignition switch OFF for 10 seconds.
    4.  
    5. Turn the ignition switch to the ON position and check for leaks.
    6.  

  12.  

 
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