GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Fuel Injectors

Print

The primary function of the nozzles is to distribute the fuel in the combustion chamber, which affects the combustion efficiency and engine performance.

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the fuel return line(s) from the fuel injector nozzle(s).
  4.  
  5. Disconnect the fuel injection line(s) from the fuel injector nozzle(s).
  6.  
  7. Remove the fuel injector nozzle(s) from the engine.
  8.  
  9. Inspect and test the fuel injector nozzle(s).
  10.  

To install:
  1. Install the fuel injector nozzle(s) to the engine.
  2.  
  3. Connect the injection line(s) to the fuel injector nozzle(s).
  4.  
  5. Connect the fuel return line(s) to the fuel injector nozzle(s).
  6.  
  7. Connect the negative battery cable.
  8.  

TESTING



See Figure 1

The following procedure requires the use of a reliable pressure tester and Calibrating Oil No. SAE J9670 or equivalent at room temperature, approximately 70°F (20°C).


CAUTION
DO NOT use diesel fuel; it is unstable with respect to corrosion inhibition and it may cause skin problems.

Opening Pressure
  1. Using a reliable pressure tester, connect the test line to a fuel nozzle and tighten the fittings.
  2.  


CAUTION
Exercise extreme care, when using the pressure tester, not to damage the gauge with excessive pressure during the test procedure. When testing the nozzle(s), be sure not to position your hands or arms near the nozzle tip. The atomized high pressure spray has enough penetrating power to puncture the flesh and destroy tissue, and may also cause blood poisoning. The nozzle tip should always be enclosed in a transparent receptacle, to contain the spray.

  1. Close the gauge valve and operate the handle several times, then check for proper nozzle spray pattern.
  2.  
  3. Open the gauge valve and operate the handle slowly to determine the injector opening pressure. Observe the gauge reading just before the oil is sprayed from the tip; a buzzing noise will occur when the spray is injected. The minimum opening pressure is 1493 psi (10,294 kPa).
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Fuel nozzle spray patterns - 2.2L diesel engine

Spray Pattern
  1. Close the pressure gauge.
  2.  
  3. Operate the handle slowly, one stroke every 2 seconds, and observe the spray pattern.
  4.  
  5. The spray should be uniform and injected at the correct angle of the nozzle being tested.
  6.  

Leakage
  1. Operate the handle to increase the fuel pressure to 284 psi (1958 kPa).
  2.  
  3. Observe the nozzle tip, it should remain dry without an accumulation of fuel at the spray holes; a slight wetting is permitted after 10 seconds, if no droplets are formed.
  4.  

 
label.common.footer.alt.autozoneLogo