GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 34730-1A Fuel Pressure Gage
    • J 34730-75 Fuel Pressure Gage Adapter

Installation Procedure

  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .
  2. 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.

  3. Disconnect the negative battery cable.

  4. Object Number: 721785  Size: MH
  5. Disconnect the fuel supply hose (2) from the fuel rail supply pipe (5). Use a shop towel in order to catch any remaining fuel that may leak.
  6. Connect the hose end of the J 34730-75  (3) to fuel rail supply pipe (5).
  7. Connect the fuel supply hose (2) to the J 34730-75  (3).
  8. Secure both connections with the hose clamps.
  9. Install the J 34730-1A  (4) to the J 41041  (3).
  10. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  11. Connect the negative battery cable.
  12. Turn ON the ignition in order to pressurize the fuel system.
  13. Turn OFF the ignition.
  14. Check for any fuel leaks and repair as necessary.
  15. Start the engine.
  16. Idle the engine at the normal operating temperature.
  17. Verify the fuel pressure as follows:
  18. • 210-260 kPa (30-37 psi) with the engine idling.
    • 270-310 kPa (39-45 psi) when the engine is not running, the ignition switch is On, and the fuel pump running.
    • The fuel pressure should hold at or more than 200 kPa (29 psi) within 1 minute of the engine not running while the ignition switch is Off and the fuel pump is not running.
  19. If the fuel pressure is not within the specifications, refer to Fuel System Diagnosis .

Removal Procedure

  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .

  2. Object Number: 721785  Size: MH
  3. Disconnect the J 34730-1A (4) from the J 41041 (3). Use a shop towel in order to catch any remaining fuel that may leak.
  4. Disconnect the fuel supply hose (2) from the J 41041 (3). Use a shop towel in order to catch any remaining fuel that may leak.
  5. Disconnect the J 41041 (3) from the fuel rail supply pipe (5). Use a shop towel in order to catch any remaining fuel that may leak.
  6. Connect the fuel supply hose (2) to the fuel rail supply pipe (5).
  7. Secure the connection with the hose clamp.
  8. Connect the negative battery cable.
  9. Turn ON the ignition in order to pressurize the fuel system.
  10. Turn OFF the ignition.
  11. Check for any fuel leaks and repair as necessary.