Chrysler Full-Size Trucks 1997-2000 Repair Guide

Relieving Fuel System Pressure

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CAUTION
The fuel injection system is under constant pressure (up to approximately 50 psi). Before servicing any part of the fuel injection system, the pressure must be released. Observe all applicable and common sense safety precautions during these procedures.

The system may or may not be fitted with a pressure test port. Check first, and then follow the appropriate procedure.


CAUTION
Whenever servicing the fuel system, always work in a well ventilated area. Do NOT allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion. Fuel system work is made more hazardous by a hot engine. Work on a cold engine whenever possible.

USING THE PRESSURE TEST PORT



This procedure requires the use of factory fuel pressure gauge tool set No. 5069, or equivalent. It relieves pressure through the pressure test port.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the fuel filler cap.
  4.  
  5. Remove the air cleaner assembly, if needed for access.
  6.  
  7. Remove the protective cap from the fuel pressure test port on the fuel rail.
  8.  
  9. Remove the gauge from the fuel pressure gauge tool set and place the gauge end of the hose into a suitable container. Screw the other end of the hose onto the fuel pressure test port and relieve the fuel pressure by venting the pressure out the hose.
  10.  
  11. Remove the gauge tool set hose.
  12.  
  13. Install a protective cap on fuel pressure test port.
  14.  
  15. Install removed components after servicing the fuel system.
  16.  



Click image to see an enlarged view

Fig. Fuel pressure test port is protected by a plastic cap. This 5.2L engine has the port on the driver's side fuel rail

BYPASSING THE PRESSURE TEST PORT



This procedure requires the use of a pair of jumper wires with alligator clips. It can be used on systems with or with a pressure test port. It relieves pressure by having the engine consume fuel in the lines and manually discharging an injector nozzle to remove the rest.

  1. Remove the fuel filler cap.
  2.  
  3. Remove the fuel pump relay from the Power Distribution Center (PDC). The location of the relay is provided on the underside of the PDC cover.
  4.  


WARNING
This may cause one or more DTCs to be set in memory.

  1. Start and run the engine until it stalls.
  2.  
  3. Attempt restarting until the engine will not run at all.
  4.  
  5. Turn the ignition key OFF .
  6.  
  7. This should have eliminated high pressure in the fuel lines. To relieve the rest of the pressure, the procedure involves manually activating an injector nozzle to empty the fuel in the rail(s).
  8.  


WARNING
Do NOT carry out the following steps unless the system has first been relieved as described above.

  1. Unplug the electrical connector from any injector. Place a suitable container beneath the injector to catch the fuel when it discharges.
  2.  
  3. Attach one end of a jumper wire (18-gauge or smaller) to either of the injector terminals.
  4.  
  5. Connect the other end of the jumper wire to the battery positive (+) terminal.
  6.  
  7. Connect a second jumper wire to the injector and ground it to the battery negative (-) terminal for two seconds.
  8.  
  9. The voltage will discharge the fuel system through the injector.
  10.  


WARNING
Do NOT leave the jumper connected for more than two seconds. To do so will damage the injector.

  1. Replace the fuel pump relay and gas cap. Clear any stored DTCs from memory.
  2.  

 
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