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Home >> Buick >> 2004 >> Century Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 134 (Engine Mechanical - 3.8L) >> Repair Instructions >> On-Vehicle Repair Instructions >> Intake Manifold Replacement - Upper >> Removal Procedure

Removal Procedure

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  2. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement (L26)  or Fuel Injector Sight Shield Replacement (L32) .
  3. Remove the air cleaner intake duct. Refer to Air Cleaner Intake Duct Replacement in Engine Controls - 3.8L.
  4. Drain the cooling system. Refer to Draining and Filling Cooling System in Engine Cooling.
  5. Remove the right spark plug wires from the ignition control module and the upper intake manifold and reposition the wires. Refer to Spark Plug Wire Replacement in Engine Controls - 3.8L.
  6. Relieve the fuel pressure. Refer to Fuel Pressure Relief Procedure in Engine Controls - 3.8L.
  7. Remove the brake booster hose (1) from the vacuum source manifold (2).
    8. Fig 1: Brake Booster Hose & Vacuum Source Manifold
    GM910975Courtesy of GENERAL MOTORS CORP.
  8. Disconnect the electrical connectors from the following:
    • Electronic throttle control (ETC)
    • EVAP purge solenoid
    • Manifold absolute pressure (MAP) sensor
    • Mass air flow (MAF) sensor
  9. Remove the exhaust gas recirculation (EGR) valve wiring harness heat shield nut (1), bolt (2) and the EGR heat shield (3).
    10. Fig 2: EGR Valve Wiring Harness Heat Shield Nut & Bolt
    GM911071Courtesy of GENERAL MOTORS CORP.
  10. Disconnect the EVAP purge solenoid pipe quick connect fitting. Refer to Quick Connect Fitting(s) Service (Plastic Collar) in Engine Controls - 3.8L.
  11. Remove the fuel rail assembly nuts (2).
    12. Fig 3: Fuel Rail Assembly & Fuel Injectors
    GM910936Courtesy of GENERAL MOTORS CORP.
  12. Remove the fuel rail assembly (1) with the fuel injectors (3).
  13. Remove the upper intake manifold bolts (1,4) and the studs (2,3).
    14. Fig 4: Upper Intake Manifold Bolts & Studs
    GM910998Courtesy of GENERAL MOTORS CORP.
  14. Clean the upper intake manifold bolt threads.
  15. Remove the upper intake manifold.
  16. Remove the upper-to-lower intake manifold carrier gasket from the upper intake manifold.
    17. Fig 5: Upper-To-Lower Intake Manifold Carrier Gasket & Upper Intake Manifold
    GM405818Courtesy of GENERAL MOTORS CORP.
  17. If the upper intake manifold is being replaced, remove the following:
    • Throttle body
    • Manifold absolute pressure (MAP) sensor
    • Positive crankcase ventilation (PCV) valve
    • Vacuum source manifold
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