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

Fuel Injector

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REMOVAL & INSTALLATION



See Figures 1 through 7



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Fig. Fig. 1: Unplug the injector electrical connection



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Fig. Fig. 2: Unfasten the fuel meter cover retaining screws ...



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Fig. Fig. 3: ... then remove the fuel meter cover



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Fig. Fig. 4: Using a metal dowel as a fulcrum and a prytool to remove the injectors from their bores



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Fig. Fig. 5: Remove the injectors ...



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Fig. Fig. 6: Remove and discard the O-ring seals



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Fig. Fig. 7: Removing the injectors from the model 220 TBI unit-4.3L engine


CAUTION
When removing the injector(s), be careful not to damage the electrical connector pins (on top of the injector), the injector fuel filter and the nozzle. The fuel injector is serviced as a complete assembly ONLY, it is an electrical component and should not be immersed in any kind of cleaner.

  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly.
  4.  
  5. At the injector connector(s), squeeze the two tabs together and pull straight up to unplug the connector from the injector.
  6.  
  7. Loosen the fuel meter cover retaining screws, then remove the cover from the fuel meter body, but leave the cover gasket in place.
  8.  
  9. Using a small pry bar and a round fulcrum, carefully pry the injector until it is free, then remove the injector from the fuel meter body.
  10.  
  11. Remove the small O-ring from the nozzle end of the injector. If equipped and removal is necessary, carefully rotate the injector's fuel filter back and forth to remove it from the base of the injector.
  12.  
  13. Remove and discard the fuel meter cover gasket.
  14.  
  15. Remove the large O-ring and back-up washer (if equipped) from the top of the counterbore of the fuel meter body injector cavity.
  16.  

To install:
  1. If removed, with the larger end of the filter facing the injector (so that the filter covers the raised rib of the injector base) install the filter by twisting it into position on the injector.
  2.  
  3. Lubricate the new O-rings with clean automatic transmission fluid, then install the small O-ring on the nozzle end of the injector. Be sure the O-ring is pressed up against the injector or injector filter (as applicable).
  4.  
  5. Install the steel backup washer (if equipped) in the top counterbore of the fuel meter body's injector cavity, then install the new large O-ring directly over the backup washer. Make sure the O-ring is properly seated in the cavity and is flush with the top of the fuel meter body casting surface.
  6.  

If the backup washer and large O-ring are not properly installed BEFORE the fuel injector, a fuel leak will likely result.

  1. Install the fuel injector into the cavity by aligning the raised lug on the injector base with the cast notch in the fuel meter body cavity. Once the injector is aligned, carefully push down on the injector by hand until it is fully seated in the cavity. When properly aligned and installed, the injector terminals will be approximately parallel to the throttle shaft.
  2.  
  3. Position a new fuel meter cover gasket, then install the cover to the body, making sure the gasket remains in position. Using a suitable threadlocking compound, install and tighten the cover retainers to 30 inch lbs. (4 Nm).
  4.  
  5. Attach the injector electrical connector(s).
  6.  
  7. Connect the negative battery cable, then turn the ignition key to the ON position to pressurize the fuel system and check for leaks.
  8.  
  9. Install the air cleaner assembly, then start the engine and check for leaks.
  10.  

Testing
  1. Unplug the electrical connection from the injector.
  2.  
  3. Have a assistant crank the engine with the electrical connection still unplugged. If there is fuel spray from one or both injectors, the injector seal may be leaking or the injector itself could be faulty.
  4.  
  5. Attach a injector test light (noid light) to one of the injector electrical connections.
  6.  
  7. Have a assistant crank the engine and observe the test light. If the light blinks, the electrical connection is working properly. If the light does not blink, check the injector connection for damage and the wiring for continuity, repair as necessary.
  8.  
  9. Perform the test on both injector electrical connections.
  10.  
  11. Attach the injector electrical connections and have your assistant crank the engine, both injectors should spray fuel. If only one injector sprays fuel, the other injector is probably faulty. If neither injector sprays fuel, check the fuel system pressure. Refer to the fuel pump test procedure in this section. Repair the fuel pump system as necessary and repeat the test.
  12.  

 
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