2004 Buick Regal LSFACTORY OEM SERVICE PROCEDURE

Installation Procedure

CAUTION: In order to reduce the risk of fire and personal injury that may result from a fuel leak, always install the fuel injector O-rings in the proper position. If the upper and lower O-rings are different colors (black and brown), be sure to install the black O-ring in the upper position and the brown O-ring in the lower position on the fuel injector. The O-rings are the same size but are made of different materials.
    Fig 1: View Of Fuel Rail
    GM12256Courtesy of GENERAL MOTORS CORP.
  1. The O-rings must be replaced on all components that are serviced.
  2. Lightly oil the fuel injector O-rings with clean engine oil.
  3. Place the fuel rail assembly on the intake manifold.
  4. Seat the fuel injectors by HAND.
    5. NOTE: Refer to Fastener Notice in Cautions and Notices.
  5. Install the fuel rail hold-down nuts.

    Tighten:  Tighten the nuts to 10 N.m (89 lb in).

  6. Install the fuel rail-hold down stud.

    Tighten:  Tighten the stud to 25 N.m (18 lb ft).

    7. Fig 2: Left Engine Mount Strut Bolt & Nut
    GM327466Courtesy of GENERAL MOTORS CORP.
  7. Install the wiring harness to the engine mount strut.
  8. Install the left engine mount strut bolt and nut.

    Tighten:  Tighten the nut to 48 N.m (35 lb ft).

    9. Fig 3: View Of Fuel Injector Electrical Harness Clip
    GM198404Courtesy of GENERAL MOTORS CORP.
  9. Install the fuel injector electrical harness clips holding harness to the front and the rear of fuel rail.
    10. Fig 4: View Of Fuel Injector Electrical Connectors
    GM198402Courtesy of GENERAL MOTORS CORP.
  10. Connect the fuel injector electrical connectors.
  11. Install the bypass valve actuator. Refer to Bypass Valve Actuator Replacement .
  12. Install the rear generator mounting bracket and generator. Refer toGenerator Replacement (3.1L) or Generator Replacement (3.8L) in Engine Electrical.
  13. Install the ignition coil wires to the coil, and the retainer clips to the top of super charger.
    14. Fig 5: View Of Vacuum Line At Pressure Regulator
    GM155470Courtesy of GENERAL MOTORS CORP.
  14. Connect the vacuum line to the fuel pressure regulator.
    15. Fig 6: Locating Fuel Feed Pipe & Fuel Return Pipe
    GM32404Courtesy of GENERAL MOTORS CORP.
  15. Connect the fuel feed pipe (2) and the fuel return pipe (1) to the fuel rail. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
  16. Connect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  17. Inspect for leaks.
    1. Turn ON the ignition for 2 seconds.
    2. Turn OFF the ignition for 10 seconds.
    3. Turn ON the ignition.
    4. Inspect for fuel leaks.
  18. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement (L36) or Fuel Injector Sight Shield Replacement (L67) in Engine Mechanical - 3.8L.
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.