2004 GMC Envoy 4WDFACTORY OEM SERVICE PROCEDURE

Removal Procedure

    Fig 1: Disconnecting/Connecting Fuel Pressure Regulator Vacuum Line
    GM730808Courtesy of GENERAL MOTORS CORP.
  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .
  2. Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical.
  3. Before removal, clean the fuel rail assembly and the cylinder head with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak the fuel rail in liquid cleaning solvent.
  4. Disconnect the fuel pressure regulator vacuum line.
    5. Fig 2: Fuel Feed And Fuel Return Pipes (Left Side Of Engine)
    GM730718Courtesy of GENERAL MOTORS CORP.
  5. Disconnect the fuel feed and return pipes (1, 2) from the fuel rail. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
  6. Disconnect the fuel injector harness in-line connector.
    7. Fig 3: Removing/Installing Fuel Rail
    GM730890Courtesy of GENERAL MOTORS CORP.
  7. Remove the fuel rail attaching bolts.
    8. NOTE:
    • Remove the fuel rail assembly carefully in order to prevent damage to the injector electrical connector terminals and the injector spray tips. Support the fuel rail after the fuel rail is removed in order to avoid damaging the fuel rail components.
    • Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages.
  8. Remove the fuel rail assembly.
    9. Fig 4: View Of Fuel Injector, Clip & O-Rings
    GM351185Courtesy of GENERAL MOTORS CORP.
  9. Remove the injector lower O-ring seal (4) from the spray tip end of each injector (3).
  10. Discard the O-ring seals.
  11. If the fuel rail is not being replaced, go to the Installation Procedure.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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