GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 Yukon XL Denali 🢒 Engine 🢒 Engine Mechanical - Hybrid (HP2) 6.0L (LFA) 🢒 Intake Manifold Replacement

Removal Procedure

    Object Number: 1964656 Size: SH

    Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

    The High Voltage Disabling procedure will perform the following tasks:

       • Identify how to disable high voltage.
       • Identify how to test for the presence of high voltage.
       • Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.
    Failure to follow the procedures exactly as written may result in serious injury or death.

  1. Perform the High Voltage Service disconnect. Refer to High Voltage Disabling.
  2. Disconnect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  3. Remove the air cleaner outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement.
  4. Remove the engine harness retainer nut (1).
  5. Remove the engine harness retainer from the stud and locator pin.
  6. Disconnect the engine harness electrical connector (2) from the evaporative emission (EVAP) canister purge solenoid.
  7. Disconnect the engine wiring harness electrical connector (3) from the manifold absolute pressure (MAP) sensor.

    8. Object Number: 1964794 Size: SH
  8. Remove the connector position assurance (CPA) retainer (1).
  9. Disconnect the engine harness electrical connector (2) from the ignition coil harness electrical connector.
  10. Disconnect the engine harness electrical connectors (3) from the left side fuel injectors.
  11. Remove the engine harness clip (4) from the ignition coil bracket stud.

    12. Object Number: 1696893 Size: SH
  12. Remove the CPA retainer (1).
  13. Disconnect the engine harness electrical connector (2) from the ignition coil harness electrical connector.
  14. Disconnect the engine harness electrical connector (3) from the throttle actuator.
  15. Remove the engine harness clip (4) from the ignition coil bracket stud.
  16. Disconnect the engine harness electrical connectors (5) from the right side fuel injectors.

    17. Object Number: 1696914 Size: SH
  17. Remove the engine harness clip (1) bolt (3).
  18. Disconnect the engine harness electrical connector (2) from the engine coolant temperature (ECT) sensor.
  19. Disconnect the generator control module electrical connector.
  20. Gather the engine harness branches and tie the harness up out of the way to the cowl panel.

    21. Object Number: 1696917 Size: SH
  21. Disconnect the EVAP canister purge tube (1) quick connect fitting from the EVAP canister purge solenoid. Refer to Plastic Collar Quick Connect Fitting Service .
  22. Disconnect the fuel feed line quick connect fitting (2) from the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .

    23. Object Number: 1696791 Size: SH
  23. Remove the positive crankcase ventilation (PCV) hose from the intake manifold fitting.
  24. Position the hose out of the way.

    25. Object Number: 1401989 Size: SH
  25. Loosen the intake manifold bolts (512).

    26. Important: The aid of an assistant may be helpful in holding the engine harness up out of the way so the upper intake manifold cover does not get caught against the engine harness.

  26. Remove the intake manifold (500).
  27. Cover the cylinder head passages in order to prevent dirt or debris from entering the passages.

    28. Object Number: 1277097 Size: SH
  28. Remove and discard the intake manifold gaskets (514).
  29. Clean and inspect the intake manifold. Refer to Intake Manifold Cleaning and Inspection.

    30. Object Number: 1697057 Size: SH
  30. Remove the upper intake manifold cover nut.
  31. Remove the upper intake manifold cover.

    32. Object Number: 1697060 Size: SH
  32. Remove the manifold absolute pressure (MAP) sensor retainer.
  33. Remove the MAP sensor and discard the MAP sensor seal.

    34. Object Number: 1697062 Size: SH
  34. Disconnect the EVAP tube quick connect fitting at the intake manifold. Refer to Plastic Collar Quick Connect Fitting Service.
  35. Disengage the retainer securing the EVAP canister purge solenoid to the fuel rail.
  36. Remove the EVAP tube and purge solenoid.

    37. Object Number: 1697064 Size: SH
  37. Remove the throttle body bolts/nuts.
  38. Remove the throttle body.
  39. Remove and discard the throttle body gasket.

    40. Object Number: 1697066 Size: SH
  40. Remove the fuel rail bolts.

    41. Important: Lift evenly on both sides of the fuel rail until all injectors are removed from their bores.

  41. Remove the fuel rail.
  42. Remove and discard the fuel injector lower O-ring seals.

Installation Procedure

    Object Number: 1697066 Size: SH
  1. Install NEW fuel injector lower O-ring seals onto the injectors.
  2. Lubricate the NEW O-ring seals with clean engine oil.

    3. Important: Push down firmly on both sides of the rail until all the injectors have been seated into their bores.

  3. Install the fuel rail.

    4. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the fuel rail bolts.

    5. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1697064 Size: SH
  5. Install a NEW throttle body gasket to the intake manifold.
  6. Install the throttle body.
  7. Install the throttle body bolts/nuts.

    8. Tighten
    Tighten the bolts/nuts to 10 N·m (89 lb in).


    Object Number: 1697062 Size: SH
  8. Install the EVAP tube and purge solenoid.
  9. Install the EVAP canister purge solenoid to the fuel rail bracket and engage the retainer.
  10. Connect the EVAP tube quick connect fitting at the intake manifold. Refer to Plastic Collar Quick Connect Fitting Service.

    11. Object Number: 1697060 Size: SH
  11. Lubricate the MAP sensor seal with clean engine oil.
  12. Install the MAP sensor with a new seal.
  13. Install the MAP sensor retainer.

    14. Object Number: 1697057 Size: SH
  14. Install the upper intake manifold cover.
  15. Install the upper intake manifold cover nut until snug.

    16. Object Number: 1277097 Size: SH
  16. Install NEW intake manifold gaskets (514) to the intake manifold.
  17. Remove the covers from the cylinder head passages.

    18. Object Number: 1401989 Size: SH
  18. Install the intake manifold (500).
  19. Apply a 5 mm (0.20 in) band of threadlock GM P/N 12345382 (Canadian P/N 10953489) to the threads of the intake manifold bolts (512). Refer to Adhesives, Fluids, Lubricants, and Sealers.

    20. Important: The aid of an assistant may be helpful in holding the engine harness up out of the way so the upper intake manifold cover does not get caught against the engine harness.

  20. Install the intake manifold bolts (512) finger tight.

    21. Object Number: 1552512 Size: SH
  21. Tighten the intake manifold bolts to specifications.

    22. Tighten

        • Tighten the bolts a first pass in the sequence shown to 5 N·m (44 lb in).
        • Tighten the bolts a final pass in the sequence shown to 10 N·m (89 lb in).

    Object Number: 1696791 Size: SH
  22. Position and install the PCV hose to the intake manifold fitting.

    23. Object Number: 1696917 Size: SH
  23. Connect the fuel feed line quick connect fitting (2) to the fuel rail. Refer to Metal Collar Quick Connect Fitting Service.
  24. Connect the EVAP canister purge tube (1) quick connect fitting to the EVAP canister purge solenoid. Refer to Plastic Collar Quick Connect Fitting Service.

    25. Object Number: 1696914 Size: SH
  25. Untie the engine harness branches from the cowl panel and position over the engine.
  26. Connect the engine harness electrical connector (2) to the ECT sensor.
  27. Position the engine harness clip (1) to the generator bracket and install the bolt (3).

    28. Tighten
    Tighten the bolt to 9 N·m (80 lb in).

  28. Connect the generator control module electrical connector.

    29. Object Number: 1696893 Size: SH
  29. Connect the engine harness electrical connectors (5) to the right side fuel injectors.
  30. Install the engine harness clip (4) to the ignition coil bracket stud.
  31. Connect the engine harness electrical connector (3) to the throttle actuator.
  32. Connect the engine harness electrical connector (2) to the ignition coil harness electrical connector.
  33. Install the CPA retainer (1).

    34. Object Number: 1964794 Size: SH
  34. Install the engine harness clip (4) to the ignition coil bracket stud.
  35. Connect the engine harness electrical connectors (3) to the left side fuel injectors.
  36. Connect the engine harness electrical connector (2) to the ignition coil harness electrical connector.
  37. Install the CPA retainer (1).

    38. Object Number: 1964656 Size: SH
  38. Connect the engine wiring harness electrical connector (3) to the MAP sensor.
  39. Connect the engine harness electrical connector (2) to the EVAP canister purge solenoid.
  40. Install the engine harness retainer to the stud and locator pin.
  41. Install the engine harness retainer nut (1).

    42. Tighten
    Tighten the nut to 5 N·m (44 lb in).

  42. Install the air cleaner outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement.
  43. Connect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  44. Perform the High Voltage Service connect. Refer to High Voltage Enabling.