Chrysler Full-Size Trucks 1967-1988 Repair Guide

Fuel Injectors

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The fuel injector is an electric solenoid driven by the power module, but controlled by the SMEC. The SMEC determines when and how long the power module should operate the injector based on various sensor input. When an electric current is supplied to the injector, a spring loaded ball is lifted from its seat. This allows fuel to flow through six spray orifices and deflects off the sharp edge of the injector nozzle. This action causes the fuel to form a 45° cone shaped spray pattern before entering the air stream in the throttle body.

REMOVAL & INSTALLATION



See Figures 1, 2 and 3

  1. Remove the air cleaner assembly.
  2.  
  3. Perform the fuel system pressure release.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Remove the fuel pressure regulator.
  8.  
  9. Remove the Torx® screw securing the injector cap.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Injector cap hold-down removal



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Fig. Fig. 2: Carefully pry upward to free the fuel injector

  1. With two small prytools, lift the cap off the injector using the slots provided.
  2.  
  3. Using a small prytool placed in the hole in the front of the electrical connector, gently pry the injector from pod.
  4.  
  5. Make sure the injector lower O-ring has been removed from the pod.
  6.  

To install:
  1. Place a new lower O-ring on the injector and a new O-ring on the injector cap. The injector should have the upper O-ring already installed.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Make sure O-rings are in place before installing the new injector

  1. Put the cap on the injector. (Injector and cap are keyed). The cap should sit on the injector without interference. Apply a light coating of castor oil or petroleum jelly on the O-rings. Place the assembly in the pod.
  2.  
  3. Rotate the cap and injector to line up the attachment hole.
  4.  
  5. Push down on the cap until it contacts the injector pod.
  6.  
  7. Install the Torx® screw and torque it to 35-45 inch lbs. (3.9-5.0 Nm).
  8.  
  9. Install the fuel pressure regulator.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Test for leaks using ATM tester C-4805 or equivalent. With the ignition in the RUN position depress the ATM button. This will activate the pump and pressurize the system. Check for leaks.
  14.  
  15. Reinstall the air cleaner assembly.
  16.  

 
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