Tools Required

J 45878 Combustible Gas Detector

Caution: 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.

Caution: 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 fuel system pressure. Refer to Fuel Pressure Relief .

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the C/K Pickup service manual.



3. Remove the tank cover (2). Refer to Fuel Tank Cover Replacement .



4. Disconnect the HPR fuel outlet line (4).



5. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information in the C/K Pickup service manual.
6. Disconnect the HPR fuel outlet line (3).
7. Remove the line from the vehicle.

1. Install the line (3) into the vehicle.

Caution: Natural gas is stored under high pressure. If a leak occurs, the high pressure could cause a personal injury. In order to prevent Compressed Natural Gas (CNG) fuel leaks, always replace the CNG fuel system O-rings during service.

2. Connect the high pressure regulator (HPR) line (3) to the underbody line (2) using a new O-ring face seal. Lubricate the O-ring with petroleum jelly.

Tighten
Tighten the fuel line to 37 N·m (27 lb ft).




3. Connect the fuel line (4) to the HPR fitting (3) using a new O-ring. Lubricate the O-ring face seal with petroleum jelly.

Tighten
Tighten the fuel line to 37 N·m (27 lb ft).

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

4. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the C/K Pickup service manual.
5. Start the vehicle and inspect for CNG fuel leaks at the serviced fitting using the J 45878 or an equivalent liquid leak detector.



6. Install the tank cover (2). Refer to Fuel Tank Cover Replacement .