GM Service Manual Online
For 1990-2009 cars only

Fuel Rail and Injectors Cleaning and Inspection LLT

Special Tools

    • EN-47909 Injector Bore and Sleeve Cleaning Kit
    • EN-48266 Injector Seal Installer and Sizer

For equivalent regional tools, refer to Special Tools.


    Object Number: 1992488  Size: SH
  1. Remove the injectors from the fuel rail.

  2. Object Number: 1992493  Size: SH
  3. Remove the wiring harness from the fuel injectors.

  4. Object Number: 1992497  Size: SH
  5. Remove and discard the fuel injector hold-down clamp.

  6. Object Number: 1992499  Size: SH
  7. Remove and discard the fuel injector O-ring and plastic spacer.

  8. Object Number: 1992501  Size: SH
  9. Remove and discard the isolator cup and retainer.

  10. Object Number: 1992504  Size: SH
  11. Remove and discard the fuel injector seal.

  12. Object Number: 1992506  Size: SH

    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.

  13. Remove and discard the fuel pressure sensor.
  14. Note: Do not soak or submerge the fuel rail or injectors in solvent.

  15. Clean the exterior of the fuel rail and injectors with solvent.

  16. Object Number: 1992509  Size: SH
  17. Inspect the fuel rail and components for the following conditions:
  18. • 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
    • Damage to the threads on the fuel rail feed fitting
    • Damage to the threads in the fuel pressure sensor bore

    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.

  19. Install the fuel pressure sensor.
  20.    Note: Ensure that the fuel rail threads have been cleaned of any excess fuel, or the NEW fuel injection fuel rail fuel pressure sensor will NOT seal properly.

    • Lubricate the threads and the sealing cone in the fuel rail with silicon free engine oil GM P/N 12345610, Canadian P/N 993193, or equivalent.
    • Lubricate the threads and the sealing cone on the NEW fuel injection fuel rail fuel pressure sensor with silicon free engine oil GM P/N 12345610, Canadian P/N 993193, or equivalent.
    • Install the NEW fuel injection fuel rail fuel pressure sensor hand tight.
    • Remove the NEW fuel injection fuel rail fuel pressure sensor, re-lubricate following steps 1 and 2 above.

    Caution: Refer to Fastener Caution in the Preface section.

    • Install the NEW fuel injection fuel rail fuel pressure sensor and tighten to 33 N·m (25 lb ft).

    Object Number: 1992512  Size: SH
  21. Inspect the fuel injectors for the following conditions:
  22. • Damage to the fuel injector connector (1)
    • Damage to the injector locator tab (2)
    • Damage to the fuel inlet cone (3)
    • Damage the plastic fuel injector body (4)
    • Damage to the isolator cup retainer groove (5)
    • Damage to the teflon seal (6)
    • Damage to the fuel injector tip (7)
  23. Replace the fuel rail or injector if any damage is found. Do not attempt to repair a fuel rail or injector.

  24. Object Number: 1992514  Size: SH
  25. Lubricate the NEW O-ring with 5W30 engine oil.
  26. Note: The plastic spacer has a top and a bottom. The top, O-ring sealing area, is wider.

  27. Install the NEW plastic spacer and O-ring on the injector.

  28. Object Number: 1992516  Size: SH
  29. Install the isolator cup and retainer.

  30. Object Number: 1992518  Size: SH

    Note: Do not use any type of lubricant when installing the NEW seal.

  31. Install a NEW seal on the injector using the EN-48266-1. The seal must be installed/slid into the recessed area of the fuel injector.

  32. Object Number: 1992521  Size: SH
  33. Compress the seal with your fingers before resizing the seal using the EN-48266-2.

  34. Object Number: 1992524  Size: SH
  35. Install a NEW fuel injector hold-down clamp.