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Home >> Cadillac >> 2017 >> CT6 Plug-In >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 24 (Engine Mechanical - 3.0L (LGW) Or 3.6L (LGX) - Repair Instructions - Off Vehicle) >> Repair Instructions - Off Vehicle >> Fuel Rail and Injectors Cleaning and Inspection

Fuel Rail and Injectors Cleaning and Inspection

WARNING: This page is about a different variant/trim than selected.

Special Tools

For equivalent regional tools, refer to Special Tools .

  1. Disconnect and remove the fuel rail wiring harness (1).
    Fig 1: View Of Fuel Rail Wiring Harness
    GM2202041Courtesy of GENERAL MOTORS COMPANY
  2. Taking care not to touch or apply force to the injector tip or electrical connector, remove the fuel injector (1) by pressing down on the retainer lever to release the tab (2) and simultaneously rotating the injector 45 degrees and pulling straight out from the fuel rail.
    Fig 2: Fuel Injector
    GM2915261Courtesy of GENERAL MOTORS COMPANY
  3. Remove the retainer (3) from the fuel injector and discard.
  4. Using pliers, remove the fuel injector bushing (3) straight out from injector body. Discard bushing (3). Remove and discard the fuel injector O-ring (1) and plastic spacers (2).
    Fig 3: Fuel Injector Components
    GM2915263Courtesy of GENERAL MOTORS COMPANY
  5. Remove and discard the fuel injector seals (4).
  6. Remove the fuel pressure sensor (1).
    Fig 4: Identifying Fuel Pressure Sensor
    GM2202044Courtesy of GENERAL MOTORS COMPANY
    NOTE: Applying force to the plastic housing of the sensor will destroy the sensor. To tighten or loosen, only apply force to the attached hexagon.
  7. Clean the exterior of the fuel rail and injectors with solvent.
    NOTE: Do not soak or submerge the fuel rail or injectors in solvent.
  8. Inspect the fuel rail (1) and components for the following conditions:
    Fig 5: Identifying Fuel Rail Inspection Areas
    GM2202045Courtesy of GENERAL MOTORS COMPANY
    • Damage, debris or restrictions to the fuel rail
    • Damage, debris or restrictions to the fuel ports in the fuel rail
    • Damage to the mounting area for the fuel rail
    • Damage to the fuel rail mounting bolts or mounting bolt grommets/isolators
    • Damage to the threads on the fuel rail feed fitting
    • Damage to the threads in the fuel pressure sensor bore
    • Damage to the fuel pressure sensor connector, threads or sealing face
  9. Install the fuel pressure sensor (1).
    Fig 6: Identifying Fuel Pressure Sensor
    GM2202044Courtesy of GENERAL MOTORS COMPANY
    NOTE: Applying force to the plastic housing of the sensor will destroy the sensor. To tighten or loosen, only apply force to the attached hexagon.
    1. Lubricate the threads and the sealing area in the fuel rail with silicon free engine oil. Refer to Adhesives, Fluids, Lubricants and Sealers for recommended lubricant.
      NOTE: Ensure that the fuel rail threads have been cleaned of any excess fuel or the fuel pressure sensor will NOT seal properly.
    2. Lubricate the threads and the sealing area on the fuel pressure sensor with silicon free engine oil. Refer to Adhesives, Fluids, Lubricants and Sealers for recommended lubricant.
    3. Install the fuel pressure sensor hand tight.
    4. Remove the fuel pressure sensor and re-lubricate.
    5. Install the fuel pressure sensor and tighten to 33 N.m (25 lb ft).
      CAUTION: Refer to Fastener Caution .
  10. Inspect the fuel injectors for the following conditions:
    Fig 7: Identifying Fuel Injector Components
    GM2202046Courtesy of GENERAL MOTORS COMPANY
    • Damage to the fuel injector connector (1)
    • Damage to the fuel inlet cone (2)
    • Damage to the fuel injector body (3)
    • Damage to the fuel injector tip (4)
  11. Replace the fuel rail or injector if any damage is found. Do not attempt to repair a fuel rail or injector.
  12. Install NEW fuel injector bushing (1) onto injector body. Bushing should seat with a distinct "snap" sound and feel. Ensure bushing is fully seated.
    Fig 8: Fuel Injector Bushing
    GM2915264Courtesy of GENERAL MOTORS COMPANY
    NOTE: The fuel injector bushing (1) is to be installed BEFORE O-ring or backup rings are installed.
  13. Install the NEW white plastic spacer (3) on the fuel injector first.
    Fig 9: Injector And Components
    GM2915265Courtesy of GENERAL MOTORS COMPANY
  14. Install the brown plastic spacer (2) second.
  15. Lubricate the NEW O-ring (1) with one drop of clean engine oil.
  16. The right side (bank 1) fuel injector wiring harness connectors (1) should point to the rear of the engine. The left side (bank 2) fuel injector wiring harness connectors (2) should point to the front of the engine.
    Fig 10: Fuel Injector Wiring Harness Connectors
    GM3968970Courtesy of GENERAL MOTORS COMPANY
    CAUTION: Ensure the fuel injectors are installed in the correct orientation. Improper orientation of the fuel injectors may result in engine misfire and possible engine damage.
  17. Install NEW retainer (3) onto the fuel injector.
    Fig 11: Injector Retainer
    GM2915262Courtesy of GENERAL MOTORS COMPANY
  18. Holding the largest diameter/body of the injector only, indicated by arrow in graphic, insert the injector assembly (1) into the fuel rail. Ensure correct orientation of the electrical connector (2).
  19. Rotate the fuel injector approximately 45 degrees until the tab on the retainer (4) locks into the notch on the fuel rail.
  20. Repeat for remaining injectors until all are installed and retained in fuel rail.
  21. Install the fuel rail wiring harness (1).
    Fig 12: View Of Fuel Rail Wiring Harness
    GM2202041Courtesy of GENERAL MOTORS COMPANY
  22. Install EN 49245-1  long protector (3) onto the fuel injector tip, covering the first recessed area closest to the tip. Place a NEW seal (2) on EN-49245-1  long protector.
    Fig 13: Identifying Fuel Injector Tip & Seals
    GM2210025Courtesy of GENERAL MOTORS COMPANY
    NOTE: Do not use any type of lubricant when installing the NEW seals (2) on the fuel injector tip.
  23. Using EN-49245-3  pusher (1), install the seal into the second recessed area (4) of the fuel injector.
  24. Compress the seal with your fingers, then resize the seal using the EN-49245-4  sizer (5).
    NOTE: The EN-49245-4  sizer is two sided and either direction will size the seal correctly.
  25. Install EN-49245-2  short protector (3) onto the fuel injector tip. Place a NEW seal (2) on EN-49245-2  short protector.
    Fig 14: Identifying Fuel Injector Tip & Seals
    GM2219104Courtesy of GENERAL MOTORS COMPANY
    NOTE: Do not use any type of lubricant when installing the NEW seals (2) on the fuel injector tip.
  26. Using EN-49245-3  pusher (1), install the seal into the first recessed area (4) of the fuel injector.
  27. Compress the seal with your fingers, then resize the seal using the EN-49245-4  sizer (5).
    NOTE: The EN-49245-4  sizer is two sided and either direction will size the seal correctly.
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