GM Service Manual Online
For 1990-2009 cars only

Fuel Hose/Pipe Replacement - Low Pressure Lock-Off to Fuel Filter Passenger/Cargo

Tools Required

J 45878 Combustible Gas Detector

Removal Procedure

    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. Object Number: 859479  Size: SH
  4. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim in the G/H Van service manual.

  5. Object Number: 893533  Size: SH
  6. Disconnect the CNG fuel line (8) from the fuel rail.
  7. Remove the fuel line P-clamp mounting bolts (9).
  8. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information in the G/H Van service manual.

  9. Object Number: 893530  Size: SH
  10. Remove the fuel line P-clamp mounting bolt (7).

  11. Object Number: 893531  Size: SH
  12. Disconnect the fuel line fitting (2) at the filter.
  13. Remove the fuel line from the vehicle.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 893531  Size: SH
  1. Connect the CNG fuel line fitting (2) to the filter using a NEW copper sealing washer.
  2. Tighten
    Tighten the fuel line fitting to 37 N·m (27 lb ft).


    Object Number: 893530  Size: SH
  3. Install the fuel line P-clamp and mounting bolt (7).
  4. Tighten
    Tighten the bolt to 10 N·m (89 lb in).


    Object Number: 893533  Size: SH
  5. Install the LEFT fuel line P-clamp and mounting bolt (9).
  6. Tighten
    Tighten the left P-clamp bolt to 34 N·m (25 lb ft)

  7. Install the RIGHT fuel line P-clamp and mounting bolt (9).
  8. Tighten
    Tighten the right P-clamp bolt to 7 N·m (62 lb in)

  9. Connect the fuel line fitting (8) to the fuel rail.
  10. Tighten
    Tighten the fuel line fitting to 37 N·m (27 lb ft)

  11. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
  12. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.

  13. Object Number: 859479  Size: SH
  14. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim in the G/H Van service manual.

Fuel Hose/Pipe Replacement - Low Pressure Lock-Off to Fuel Filter Cutaway

Tools Required

J 45878 Combustible Gas Detector

Removal Procedure

    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. Object Number: 859479  Size: SH
  4. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim in the G/H Van service manual.

  5. Object Number: 893533  Size: SH
  6. Disconnect the CNG fuel line (8) from the fuel rail.
  7. Remove the fuel line P-clamp mounting bolts (9).
  8. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information in the G/H Van service manual.

  9. Object Number: 893530  Size: SH
  10. Remove the fuel line P-clamp mounting bolt (7).

  11. Object Number: 893528  Size: SH
  12. Disconnect the fuel line fitting (3) at the filter.
  13. Remove the fuel line from the vehicle.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 893528  Size: SH
  1. Connect the CNG fuel line fitting (3) to the filter using a NEW copper sealing washer.
  2. Tighten
    Tighten the fuel line fitting to 37 N·m (27 lb ft).


    Object Number: 893530  Size: SH
  3. Install the fuel line P-clamp and mounting bolt (7).
  4. Tighten
    Tighten the bolt to 10 N·m (89 lb in).


    Object Number: 893533  Size: SH
  5. Install the LEFT fuel line P-clamp and mounting bolt (9).
  6. Tighten
    Tighten the left P-clamp bolt to 34 N·m (25 lb ft)

  7. Install the RIGHT fuel line P-clamp and mounting bolt (9).
  8. Tighten
    Tighten the right P-clamp bolt to 7 N·m (62 lb in)

  9. Connect the fuel line fitting (8) to the fuel rail.
  10. Tighten
    Tighten the fuel line fitting to 37 N·m (27 lb ft)

  11. Install the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical in the G/H Van service manual.
  12. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.

  13. Object Number: 859479  Size: SH
  14. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim in the G/H Van service manual.