Removal Procedure (1998 Models)
Tools Required^ J 42435 CNG Tank Venting Kit
^ J 43602 HPL Crowfoot
^ J 42309 CNG Tank Sling
Caution:
Do not install this part if you can not completely refill the vehicle with Compressed Natural Gas (CNG) after a repair. Failure to properly leak-check the system after the part replacement may result in serious personal injury or damage to the vehicle or the part.
1. Remove the fuel tank cover. Refer to CNG Fuel Tank Cover Replacement in the Body Rear End subsection of the Bi-Fuel Supplement Service Manual.
2. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief Procedure (1998).
Caution:
Before servicing any electrical component, the ignition key must be in the OFF or LOCK position and all electrical loads must be OFF unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.
3. Disconnect the negative battery cable.
4. Disconnect the following electrical connectors:
^ High pressure lock-off (HPL) (1)
^ Fuel temperature sensor (FTS) (2)
^ Fuel pressure sensor (FPS) (3)
Notice:
The manual valve opening tool may damage the main seat of the high pressure lock-off (HPL) if used improperly. Use this tool only when the HPL is not in operation.
Important:
Venting of natural gas to the atmosphere may be prohibited in some areas. Before venting the CNG fuel tank, contact the local gas company to assure that all local, state and federal regulations are observed.
5. In order to prevent freeze damage to the fill line and the FPS, the tank fittings must be capped by performing the following steps:
5.1. Remove the fuel pressure sensor (FPS).
5.2. Install a fitting and cap (2) supplied from the J 42435 CGN Tank Venting Kit into the FPS port (1).
5.3. Disconnect the fill line.
5.4. Install a cap (3) supplied from the J 42435 onto the fill line port fitting (4).
5.5. Disconnect the fuel outlet line.
5.6. Leave the relief port (top hole) open.
6. Connect the vent hose (1) to the fuel outlet fitting and to the vent stack.
Caution:
When venting the Compressed Natural Gas (CNG) fuel tank, take the following precautions in order to prevent fire and personal injury:
^ Use the proper grounding procedure to an earth ground in order to prevent a build-up of static electricity which can lead to an electrical discharge.
^ Use the J 42435 CNG Tank Vent Kit with a vent stack.
^ Vent the CNG fuel tank in a well ventilated work area.
^ Keep sparks, flames, and smoking material away from the area.
^ Wear the appropriate hearing protection during the venting procedure. A sudden pressure loss from an uncontrolled gas leak may cause hearing damage.
7. Connect the ground strap (2) (attached to the vent hose) to the HPL and the vent stack (earth) ground.
8. Remove the manual shut-off fitting from the HPL.
9. Before installing the manual vent tool, count the number of turns required to rotate the tool from fully retracted to fully extended. When venting the CNG tank, ensure that you rotate the tool the same number of turns. This will ensure that the HPL pilot valve is un-seated and the tank is vented. Some pressure should always vent from the CNGC tank.
Verify that the manual vent tool supplied from the J 42435 is in the non-venting position with the Allen screw fully seated counterclockwise.
10. Install the manual vent tool into the HPL port.
11. Slowly turn the manual vent tool Allen screw clockwise until natural gas begins to vent.
12. Allow the CNG fuel tank to vent until the pressure gauge reads 0 kPa (0 psi). If the tank stops venting and pressure is indicated on the J 42435 gauge, inspect the vent line for a frozen fitting. The fitting will eventually thaw and fuel will again continue to vent.
Do not leave the tank unsupervised.
13. Disconnect the vent hose (1) from the HPL.
14. Remove the manual vent tool and all fittings.
15. Remove the fuel inlet fitting from the HPL and discard the O-rings.
16. Remove the fuel outlet fitting from the HPL and discard the O-rings.
17. Using the J 43602 HPL Crowfoot removal tool, loosen the HPL.
18. Mark the tank in two places approximately 180 degrees apart for tank re-installment reference.
19. Remove the upper mounting bracket nuts and bolts and retain them.
20. Remove the clevis and bridge pins.
21. Remove the upper mounting brackets.
22. Use the J 42309 CNG Tank Sling and a lifting device in order to remove the tank from the vehicle enough to allow removal of the HPL from the tank.
23. Unscrew and remove the HPL and the O-ring from the tank.