GM Full Size Vans 1987-1997 Repair Guide

Fuel Injectors

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REMOVAL & INSTALLATION



See Figure 1

Use care when removing the injectors to prevent damage to the electrical connector pins on the injector and the nozzle. The fuel injector is serviced as a complete assembly only. Since the injector is an electrical component, it should not be immersed in any type of cleaner.

  1. Disconnect the negative battery cable.
  2.  
  3. Relieve the fuel system pressure. Refer to the fuel system relief procedure in this section.
  4.  
  5. Remove the intake manifold plenum.
  6.  
  7. Remove the fuel rail assembly.
  8.  
  9. Disengage the electrical wiring harness.
  10.  
  11. Disassemble the injector clip and discard it.
  12.  
  13. Remove the injector O-ring seals from both ends of the injector. Save the O-ring backups for use on reassembly.
  14.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the fuel injector assembly

To install:
  1. Install the O-ring backups before installing the O-rings.
  2.  
  3. Lubricate the new injector O-rings with clean engine oil and install them on the injector assembly.
  4.  
  5. Install the fuel injector into the fuel rail injector socket with the electrical connectors facing outward.
  6.  
  7. Install new injector retaining clips on the injector fuel rail assembly by sliding the clip into the injector groove as it snaps onto the fuel rail.
  8.  
  9. Install the fuel rail assembly.
  10.  
  11. Install the manifold plenum.
  12.  
  13. Engage the electrical wiring harness.
  14.  
  15. Connect the negative battery cable.
  16.  

TESTING



See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: A noid light can be attached to the fuel injector harness in order to test for injector pulse

This test requires the use of fuel injector tester J-34730-3 or its equivalent.

  1. With the engine cool and the ignition turned OFF , install the fuel pressure gauge to the fuel pressure connection. Wrap a shop towel around the fitting while connecting the gauge to prevent spillage.
  2.  
  3. Disengage all the fuel injector electrical connectors. Engage the tester to one fuel injector.
  4.  
  5. Turn ON the ignition and bleed the air from the pressure gauge.
  6.  
  7. Turn OFF the ignition for ten seconds and then turn it ON again. This will bring the fuel pressure to its maximum pressure. Record this reading.
  8.  
  9. Press the tester button and record the lowest pressure reading. Subtract this reading from the initial reading obtained and record the result.
  10.  
  11. Connect the tester to each injector and repeat Steps 4 and 5.
  12.  
  13. Pressure should fall between 56-62 psi (430 kPa). Replace any injector that does not meet these specifications.
  14.  

See Figure 3



Click image to see an enlarged view

Fig. Fig. 3: Fuel injector testers can be purchased or sometimes rented

 
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