Fuel Hoses/Pipes Replacement - Filter to Tank Pickup with Type 2 Tank

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 fuel outlet line (4) at the HPL tee fitting (3).



5. Disconnect the line at the fuel filter inlet (5).
6. Disconnect the fuel line hold down clips (3,4).
7. Remove the line from the vehicle.

1. Install the line 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 line to the fuel filter inlet fitting (5) 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 outlet line (4) to the HPL tee fitting (3) with a new O-ring face seal. Lubricate the O-ring face seal with petroleum jelly.

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




4. Install the fuel line hold down clips (3,4).

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.

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



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

Fuel Hoses/Pipes Replacement - Filter to Tank Cab/Chassis

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 truck body as required on ZW9 equipped vehicles in order to gain access to the CNG fuel tank.



4. Disconnect the fuel filter inlet line (2).
5. Remove the fuel line retainer clips (1).



6. Disconnect the fuel outlet line (3) at the high pressure lock-off (HPL).
7. Remove the line from the vehicle.

1. Install the line 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 line (3) to the HPL outlet fitting with a new O-ring face seal. Lubricate the O-ring with petroleum jelly.

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




3. Connect the line to the filter inlet (2) with a new O-ring face seal. Lubricate the O-ring face seal with petroleum jelly.

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

4. Install the fuel line retainer clips (1).

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.

5. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the C/K Pickup service manual.
6. Start the vehicle and inspect for CNG fuel leaks at all serviced fittings using the J 45878 or an equivalent liquid leak detector.
7. Install the truck body as required on ZW9 equipped vehicles.

Fuel Hoses/Pipes Replacement - Filter to Tank Pickup with Type 4 Tank

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 high pressure regulator (HPR) fuel inlet line (3).



5. Remove the HPR fuel inlet fitting (6). Capture the filter spring (4), filter (3) and seal (2) that are located behind the inlet fitting.




Important: Do not hold the HPR using the HPR cover hex flange. As required wedge a wrench between the HPR and the tank frame in order to keep the HPR from spinning in the bracket.

6. Remove the HPR mounting nut (1).



7. Disconnect the HPR coolant hoses from the lower tank cover mounting bracket retainers.
8. Disconnect all fuel line mounting clips as necessary.
9. Remove the lower tank cover mounting bracket bolts (2).
10. Set aside the mounting bracket assembly.



11. Disconnect the fuel line at the high pressure lock-off (HPL) solenoid (1).
12. Disconnect the HPL fuel line (5) at the check valve tee.
13. Disconnect the filter fuel line (4) at the check valve tee.



14. Disconnect the fuel line at the fuel filter inlet (5).
15. Disconnect the fuel line hold down clips (3, 4).
16. Remove the fuel line from the vehicle.

1. Install the fuel line into the vehicle.

Notice: Refer to Compressed Natural Gas (CNG) O-Ring Caution in the Preface section.

Notice: Refer to Fastener Notice in the Preface section.

2. Connect the fuel line to the fuel filter inlet fitting (5) with 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 filter line (4) to the check valve tee with a new O-ring face seal. Lubricate the O-ring face seal with petroleum jelly.

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

4. Connect the HPL line (5) to the check valve tee with a new O-ring face seal. Lubricate the O-ring face seal with petroleum jelly.

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

5. Connect the HPL line (1) to the HPL with a new O-ring face seal. Lubricate the O-ring face seal with petroleum jelly.

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




6. Slide the lower tank cover mounting bracket over the HPR and into position.
7. Install the lower tank cover mounting bracket and bolts (2).

Tighten
Tighten the bolts to 50 N·m (37 lb ft).

8. Attach the HPR coolant hoses to the lower tank cover mounting bracket retainers.




Important: Do not hold the HPR using the HPR cover hex flange. As required wedge a wrench between the HPR and the tank frame in order to keep the HPR from spinning in the bracket.

9. Install the HPR mounting nut (1).

Tighten
Tighten the nut to 54 N·m (40 lb ft).




10. Install the filter spring (4), filter (3) and seal (2) into the HPR inlet port.

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.

11. Install the HPR fuel inlet line fitting (6) with a new O-ring. Lubricate the O-ring with petroleum jelly.

Tighten
Tighten the fuel line fitting to 48 N·m (35 lb ft).




12. Fasten the fuel line at the lower tank cover mounting bracket (4) and the tank strap (3).



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

Tighten
Tighten the fitting 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.

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



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