Compressed Natural Gas High Pressure Regulator Replacement

Compressed Natural Gas High Pressure Regulator Replacement

Special Tools

J-45878 - Combustible Gas Detector

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Removal Procedure

Warning

Natural gas is highly flammable. In order to reduce the risk of fire and personal injury, keep sparks, flames, and smoking materials away from the vehicle while you perform the Compressed Natural Gas (CNG) fuel system service.

Warning

The Compressed Natural Gas (CNG) system operates at pressures up to 24820 kpa (3600 psi). Relieve the CNG fuel system pressure before servicing CNG fuel system components in order to reduce the risk of fire and personal injury.

1. Relieve the compressed natural gas (CNG) fuel system pressure. Refer to Compressed Natural Gas Fuel Pressure Relief (With CH-48027) Service and Repair.

2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection Battery Negative Cable Disconnection and Connection.

3. Raise the vehicle. Refer to Lifting and Jacking the Vehicle Service and Repair.

4. Remove the mid ship tank cover. Refer to Compressed Natural Gas Tank Cover Replacement - Midship Tank Compressed Natural Gas Tank Cover Replacement - Midship Tank.





5. Close the red 1/4 turn valve at the high pressure regulator (HPR).





6. Carefully loosen and disconnect the high pressure line to the HPR to relieve residual pressure.

7. Disconnect the low pressure line fitting at the HPR outlet.

8. Disconnect the electrical connections.

9. Remove the HPR assembly bracket nuts and washers.

10. Install coolant hose pinch-off tool to coolant lines and place a drain pan under the HPR assembly.

11. Mark and remove coolant lines.






Installation Procedure





1. Connect coolant lines to the original port locations on the HPR.

Caution:
Refer to Fastener Caution Fastener Caution.

2. Install HPR bracket assembly and torque to spec.

3. Connect all electrical connections.

4. Connect Fuel lines and torque to spec.

* Tighten the HPR bracket nuts to 40 Nm (29.5 lb ft).

* Tighten the high pressure fuel line fittings to 35 Nm (26 lb ft).

* Connect the low pressure fuel line fitting to the HPR outlet fitting using a NEW O-ring. Lubricate the new O-ring with petroleum jelly or equivalent before installation. Tighten the low pressure fuel line tube nuts to 45 Nm (33 lb ft)

5. Open ALL the CNG tank valves.

6. Install ALL the fuel tank covers. Refer to Compressed Natural Gas Tank Cover Replacement - Aft Tank Compressed Natural Gas Tank Cover Replacement - Aft Tank , Compressed Natural Gas Tank Cover Replacement - Cargo Tank Compressed Natural Gas Tank Cover Replacement - Cargo Tank and Compressed Natural Gas Tank Cover Replacement - Midship Tank Compressed Natural Gas Tank Cover Replacement - Midship Tank.

7. Open 1/4 turn valve.

8. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection Battery Negative Cable Disconnection and Connection.

9. Add coolant if necessary. Refer to Cooling System Draining and Filling (Static Fill) Cooling System Draining and Filling (Static Fill)Cooling System Draining and Filling (Vac N Fill) Cooling System Draining and Filling (Vac N Fill)Cooling System Draining and Filling (Static Fill Diesel) Cooling System Draining and Filling (Static Fill).

10. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J-45878 - detectoror an equivalent leak detector.