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 CNG fuel system pressure. Refer to Fuel Pressure Relief .
2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
3. Before removal, clean the fuel rail with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak fuel rails in liquid cleaning solvent.



4. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim in the G/H Van service manual.



5. Disconnect the fuel rail pressure (FRP) sensor electrical connectors (4).



6. Remove the FRP sensor (13) and discard the O-ring.

Notice: Refer to Fastener Notice in the Preface section.




1. Install the fuel rail pressure (FRP) sensor (13) using a new O-ring. Lubricate the O-ring with petroleum jelly or equivalent before installation.

Tighten
Tighten the FRP sensor to 8 N·m (71 lb in).




2. Connect the FRP electrical connector (4).
3. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
4. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.



5. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim in the G/H Van service manual.