Isuzu Cars and Trucks 1981-1991

Fuel Injector

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INSPECTION, REMOVAL AND INSTALLATION
4XC1-T I-Mark, Impulse G200Z and 4ZC1-T engine
  1. Disconnect the injector harness connector and measure the resistance between the injector terminals. Resistance should be 23 ohms. Reconnect the harness.
  2.  
  3. With the engine running, listen to the injector noise with a stethoscope. Normal operation is indicated when a regular click is heard which varies with engine speed. If a regulator click is not heard, the injector is malfunctioning.
  4.  
  5. Test for leakage, remove the common chamber and all injectors with the fuel hoses connected. Turn ON the fuel pump with engine NOT running. The leakage should be less than 2 drops per minute.
  6.  
  7. Install the injectors and common chamber.
  8.  

4XE1 Engine

For diagnostic procedures, refer to the "Emission Control Diagnosis" procedure for this engine in .

  1. Release the fuel pressure and disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner duct hose from the common chamber.
  4.  
  5. Disconnect the accelerator cable and remove the throttle body from the common chamber.
  6.  
  7. Release the canister holding clip without disconnecting the vacuum lines and place out of the way.
  8.  
  9. Remove the breather hose from the valve cover.
  10.  
  11. Disconnect the pressure regulator and fuel lines from the fuel rail.
  12.  
  13. Disconnect the injection harness from the injectors, being careful not to damage the injector terminals.
  14.  
  15. Remove the two fuel rail attaching bolts.
  16.  
  17. Disconnect the fuel lines and remove the fuel rail assembly with the injectors.
  18.  
  19. Release the injector retaining clips and remove the injectors.
  20.  



Click image to see an enlarged view

Fig. Fuel rail and injectors 4XE1 engine

To install:

  1. Lubricate the injector seals with motor oil and install the injector into the fuel rail. Lock the retaining clip.
  2.  
  3. Install the fuel rail assembly and connect the fuel lines. Make sure all seals are positioned properly and use backup wrenches on the fuel lines.
  4.  
  5. Install the two fuel rail attaching bolts.
  6.  
  7. Connect the injection harness to the injectors, being careful not to damage the injector terminals.
  8.  
  9. Connect the pressure regulator and fuel lines to the fuel rail.
  10.  
  11. Install the breather hose to the valve cover.
  12.  
  13. Install the canister holding clip.
  14.  
  15. Install the throttle body and connect the accelerator cable to the common chamber.
  16.  
  17. Install the air cleaner duct hose to the common chamber.
  18.  
  19. Connect the negative battery cable, start the engine and check for leaks.
  20.  

4ZE1 Engine
  1. Disconnect the engine harness and dropping resistor connectors and measure the resistance across the terminals. Refer to the illustration.
  2.  
  3. The resistance reading should be 23 ohms.
  4.  
  5. With the engine running, listen to the injector noise with a stethoscope. Normal operation is indicated when a regular click is heard which varies with engine speed. If a regulator click is not heard, the injector is malfunctioning.
  6.  
  7. Test for leakage, remove the common chamber and all injectors with the fuel hoses connected. Turn ON the fuel pump with engine NOT running. The leakage should be less than 2 drops per minute.
  8.  

The engine is equipped 4 fuel injectors, with one located at each cylinder.

  1. Relieve the fuel pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Label and disconnect the electrical connectors from the fuel injectors.
  6.  
  7. Disconnect the fuel rail from the fuel system.
  8.  
  9. Remove the fuel rail from the intake manifold; pull the fuel rail with the injectors connected from the intake manifold.
  10.  
  11. Separate the fuel injectors from the fuel rail.
  12.  



Click image to see an enlarged view

Fig. Fuel injector check 4ZE1 engine



Click image to see an enlarged view

Fig. Injector harness connector wiring

To install:

  1. Replace the fuel injector O-rings.
  2.  
  3. Install the fuel injectors to the fuel rail.
  4.  
  5. Lubricate the fuel injector O-rings with automatic transmission fluid and press them, with the fuel rail, into the intake manifold.
  6.  
  7. Install the fuel rail-to-intake manifold bolts.
  8.  
  9. Connect the fuel rail to the fuel system.
  10.  
  11. Connect the electrical connectors to the fuel injectors.
  12.  
  13. Connect the negative battery cable.
  14.  
  15. Turn the ignition switch ON and check for fuel leaks at the fuel rail.
  16.  

V6 Engine

The engine is equipped with 2 fuel injectors, both are located in the throttle body.

  1. Relieve the fuel pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the air cleaner.
  6.  
  7. At the injector electrical connectors, squeeze the 2 tabs together and pull them straight upward.
  8.  
  9. Remove the fuel meter cover and leave the cover gasket in place.
  10.  
  11. Using a small pry bar, carefully pry the injectors upward until they are free of the throttle body.
  12.  
  13. Remove the small O-ring from the nozzle end of the injector. Carefully rotate the injector's fuel filter back-and-forth to remove it from the base of the injector.
  14.  
  15. Discard the fuel meter cover gasket.
  16.  
  17. Remove the large O-ring and back-up washer from the top of the counterbore of the fuel meter body injector cavity.
  18.  



Click image to see an enlarged view

Fig. Fuel injector removal V6 engine

To install:

  1. Lubricate the O-rings with automatic transmission fluid and push them into the fuel injector cavities.
  2.  
  3. Install the new fuel meter cover gasket and cover.
  4.  
  5. Install the electrical connectors to the injectors.
  6.  
  7. Install the air cleaner and connect the negative battery cable.
  8.  

 
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