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Home › Cadillac › 2005 › Escalade EXT › Repair and Diagnosis › Engine Performance › System › Engine Control System - 4.8L, 5.3L & 6.0L - Introduction › Repair Instructions › Fuel Rail Assembly Replacement (5.3L (L59) Engine) › Removal Procedure

Removal Procedure

    IMPORTANT: The L59 E85 fuel rail is comprised of a material that is compatible with fuel that has a concentration of up to 85 percent ethanol. The E85 fuel rail also uses an E85 Denso fuel injectors. Because of this, special procedures will be used in servicing the fuel rail and associated components. The screws that fasten the retaining clips for the crossover pipe to the fuel rails are thread cutting and therefore should NOT be removed from the fuel rail. The fuel rail will be serviced as an entire component.
    IMPORTANT: An 8-digit identification number (1) is located on the fuel rail. Refer to this model identification number if service or part replacement is required.
    Fig 1: Fuel Rail Identification Number Location
    GM380659Courtesy of GENERAL MOTORS CORP.
  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .
    2. Fig 2: View Of EVAP Canister Purge Solenoid & Generator Electrical Connectors & Bracket Nut
    GM1235683Courtesy of GENERAL MOTORS CORP.
  2. Remove the wire harness bracket nut (2).
  3. Disconnect the evaporative emission (EVAP) purge solenoid electrical connector (1).
  4. Disconnect the generator electrical connector (3).
    5. Fig 3: View Of MAP Sensor & Knock Sensor Electrical Connectors
    GM679510Courtesy of GENERAL MOTORS CORP.
  5. Disconnect the following electrical connectors:
    • Manifold absolute pressure (MAP) sensor (1)
    • Knock sensor (2)
  6. Remove the knock sensor harness connector from the intake manifold.
    7. Fig 4: View Of Main Ignition Coil Wire Harness Connector & Clips
    GM757686Courtesy of GENERAL MOTORS CORP.
  7. Remove the connector position assurance (CPA) retainer.
  8. Disconnect the following electrical connectors from both sides of the engine:
    • Main coil (2)
    • Fuel injectors
  9. Remove the harness clips from the fuel rail (1).
  10. Reposition the upper engine wire harness aside.
    11. Fig 5: CPA Retainer & Tab
    GM820977Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: When disconnecting the Multec® 2 fuel injector connectors, DO NOT use pliers or other hand tools, as the connector ends may become mangled and be rendered unusable.
  11. Perform the following steps in order to disconnect the fuel injector electrical connectors:
    1. Mark the connectors to their corresponding injectors to ensure correct reassembly.
    2. Pull the connector position assurance (CPA) retainer (2) on the connector up 1 click.
    3. Push the tab (1) on the connector in.
    4. Disconnect the fuel injector connector electrical connector.
    5. Repeat the steps for each injector connector.
    12. Fig 6: View Of PCV Hose
    GM1201537Courtesy of GENERAL MOTORS CORP.
  12. Remove the positive crankcase ventilation (PCV) hose.
    13. Fig 7: View Of EVAP/Fuel Hose/Pipes
    GM856643Courtesy of GENERAL MOTORS CORP.
  13. Disconnect the fuel feed and return pipes (1, 2) from the fuel rail. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
  14. Disconnect the fuel pressure regulator vacuum line.
    15. Fig 8: View Of Fuel Injector Rail
    GM260176Courtesy of GENERAL MOTORS CORP.
  15. Remove the fuel rail bolts.
    16. 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.
    IMPORTANT: Before removal, if necessary, clean the fuel rail assembly with a spray type engine cleaner, use GM X-30A or equivalent. Follow the package instructions. Do not soak fuel rail assembly in any liquid cleaning solvents.
  16. Remove the fuel rail.
    17. Fig 9: View Of Fuel Injector, Clip & O-Rings
    GM351185Courtesy of GENERAL MOTORS CORP.
  17. Remove the fuel injector lower O-ring seal (4) from each injector, if necessary.
  18. Discard the O-ring seal.
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