Isuzu Cars and Trucks 1981-1991

Fuel Injector

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REMOVAL AND INSTALLATION
  1. Relieve the fuel system pressure.
  2.  
  3. Remove the fuel pressure line(s) and return line(s) from the fuel injector(s).
  4.  
  5. Remove the fuel injector(s) from the engine.
  6.  
  7. Remove the O-rings from the fuel injector.
  8.  

To install:

  1. Using new O-rings, lubricate them in diesel fuel and install them onto the fuel injector(s).
  2.  
  3. Install the fuel injector(s) into the engine.
  4.  
  5. Using new O-rings, install the fuel pressure line(s) and return line(s) onto the fuel injector(s).
  6.  

INSPECTION

CAUTION
When using the injector tester, test fluid will spray out of the injector nozzle at great pressure which can easily puncture the skin or eyes. Since a defective injector may spray in any direction, make sure the hands and eyes are placed away from the injector outlet and protective clothing and safety glasses are used.

Injector Opening Pressure Test

Remove the injector and install a injector tester J-28829 or equivalent. Measure the injector pressure.



4FB1 engine: 1706 psi (120 kg/cm)
 
C223 engine: 1493 psi (105 kg/cm)
 
C223-T engine:1920 psi (135 kg/cm)
 



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Fig. Checking nozzle opening pressure

Injector Leakage Test

Using the injector tester J-28829, maintain a pressure of 284 psi (20 kg/cm). If there is no leakage, the injector is satisfactory.

Injector Spray Pattern

Observe the spray pattern coming from the outlet. It should be a fine uniform spray. If not, clean or replace injector.



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Fig. Views of injector spray patterns the left pattern is good, the others are bad

DISASSEMBLY AND ASSEMBLY
4FB1 Engine
  1. Remove the injector from the vehicle.
  2.  
  3. Place the injector in a vise clamping the hexagonal portion in the vise. Loosen the retaining nut and remove it.
  4.  
  5. Remove the nozzle, spacer and pushrod.
  6.  
  7. Remove the nozzle spring, adjusting shim and nut.
  8.  
  9. Remove the gasket from the nozzle body.
  10.  
  11. Injector opening pressure adjustment:
  12.  
    1. Using the injector holder and injector tester. Adjust the opening pressure by setting pressure adjusting shim until desired pressure is obtained.
    2.  
    3. The injector pressure can be at a rate of 68 psi (4.8 kg/cm) every thickness change of the shim by 0.04mm. Add one 0.05mm to increase the pressure by 85 psi (6 kg/cm).
    4.  

  13. Install the injector components and torque the retaining nut to 65 ft. lbs. (88 Nm).
  14.  



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Fig. Injector nozzle 4FB1 diesel engine



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Fig. Injector nozzle adjuster

C223 and C223-T Engine
  1. Remove the injector from the vehicle.
  2.  
  3. Place the injector in a vise clamping the hexagonal portion in the vise. Loosen the retaining nut and remove it.
  4.  
  5. Remove the eye bold, gasket, cap nut and gasket.
  6.  
  7. Remove the adjusting screw, nozzle spring and pushrod.
  8.  
  9. Remove the inlet connector, gasket and retaining nut.
  10.  
  11. Remove the setting screw and nozzle holding body.
  12.  
  13. Injector opening pressure adjustment: Using the injector holder and injector tester. Adjust the opening pressure by setting pressure adjusting screw until desired pressure is obtained.
  14.  
  15. Install the cap nut and torque to 22 and 1929 ft. lbs. (34 Nm).
  16.  
  17. Assembly the injector and torque the retaining nut to 65 ft. lbs. (88 Nm).
  18.  



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Fig. Injector nozzle C223 and C223-T diesel engine



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Fig. Injector nozzle adjuster C223 and C223-T diesel engine

CLEANING

Remove the carbon from the outside of the nozzle body with a soft brush. Clean the sac portion of the body with a rod J-28826-2. Clean the nozzle seat of the body with a cleaning tool J-28826. Clean the injection hole of the body with a rod J-28826-4.



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Fig. Injector cleaning

 
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