GM Full-Size Trucks 1988-1998 Repair Information

Fuel Injectors

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REMOVAL & INSTALLATION



See Figure 1



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Fig. Fig. 1: Injection nozzles-6.2L and 6.5L engines

Special tool J-29873, or its equivalent, an injection nozzle socket, will be necessary for this procedure.

  1. Disconnect the batteries.
  2.  
  3. Disconnect the fuel line clip, and remove the fuel return hose.
  4.  
  5. Remove the fuel injection lines as previously detailed.
  6.  
  7. Using GM special tool J-29873, remove the injector. Always remove the injector by turning the 30mm hex portion of the injector; turning the round portion will damage the injector. Always cap the injector and fuel lines when disconnected, to prevent contamination.
  8.  

To install:
  1. Always install the injector by turning the 30mm hex portion of the injector; turning the round portion will damage the injector.
  2.  
  3. Install the injector with a new gasket and tighten to 50 ft. lbs. (70 Nm). Connect the injection line and tighten the nut to 20 ft. lbs. (25 Nm). Install the fuel return hose, fuel line clips, and connect the batteries.
  4.  

TESTING



  1. Install a suitable pressure gauge.
  2.  
  3. Open the shut-off valve on the gauge a 1 / 4 turn.
  4.  


CAUTION
When testing nozzle opening pressure, always keep your hands (or any exposed skin!) away from the nozzle. Diesel injectors have sufficient pressure to penetrate your skin!

  1. Slowly depress the lever on the gauge. Note when the needle on the gauge stops-the maximum pressure is the opening pressure. Pressure should never fall below 1500 psi (10,342 kPa) on the 6.2L engine or 1700 psi (11,721 kPa) on the 6.5L engine.
  2.  
  3. Replace any injector which does not meets these pressures.
  4.  

 
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