Tools Required

Important: Refer to Engine Controls Component Views for fuel injector locations. Failure to identify the correct cylinder will result in misdiagnosis.

1. Remove the lower valve cover. Refer to Valve Rocker Arm Cover Replacement - Lower Left Side or Valve Rocker Arm Cover Replacement - Lower Right Side in Engine Mechanical - 6.6L.

Important: When the fuel injector pressure lines are removed, debris may fall into the fuel injector inlet fitting. Remove any debris from the inlet fitting of the fuel injector.

Important: Confirm which side of the banjo washers have the largest outer diameter.

2. Remove the fuel injector return line from fuel injectors.
3. Remove the bolt from the fuel injector bracket.



4. Install J 44639 (2) onto the injector retainer bracket.
5. Install a wrench onto J 44639 (2) and pry away from the fuel injector (1).
6. Remove the fuel injector(s).
7. Remove the copper compression washer from the injector hole if the washer was not removed with the injector.

Important: If reusing the old injectors perform the following:

Notice: The fuel injector must be cleaned with the proper cleaning equipment. DO NOT use abrasive cleaning methods, such as a metallic brush, to remove deposits. Cleaning an injector with improper tools will damage the fuel injector.

1. Use a soft bristle non-metallic brush and top engine cleaner, GM P/N 1052626 (Canadian P/N 993026) or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before re-installation.
2. Inspect the fuel injector nozzle tip (1) for any signs of discoloration (dark yellow, tan, or blue) due to excessive heat.
3. Replace the injector if any damage is found.



4. Clean the fuel injector high pressure line.
5. Inspect the fuel injector high pressure line for excessive corrosion or damage to the sealing surfaces (1, 2). Replace the line if any damage is found.

Important: The procedure below will aid in the cleaning of carbon deposits from the injector sleeve during an injector replacement

1. Install the radial brush (brass) (EN-47909-2), to the handle assembly (EN-47909-1).
2. Insert the brush into the injector bore and rotate the handle in order to break loose any carbon deposits from the injector bore walls and the combustion deck hole.

Caution: Wear safety glasses in order to avoid eye damage.

3. Using compressed air, evacuate any debris from the injector bore.
4. Remove the radial brush from the handle assembly.
5. Install the axial brush (nylon) (EN-47909-3), to the handle assembly (EN-47909-1).
6. Insert the axial brush into the injector bore and rotate the handle while also applying a slight downward pressure, in order to force the brush ends into the bottom corners of the injector bore.

Caution: Wear safety glasses in order to avoid eye damage.

7. Using compressed air, evacuate any debris from the injector bore.

Notice: Do not allow excessive amounts of solvent to go into the cylinder during cleaning. Failure to do so may cause engine damage upon startup.

8. Lightly dampen a cotton swab (EN-47909-20) with GM Top Engine Cleaner, P/N 1052626 (Canadian P/N 993026) or equivalent, and wipe away any deposits from the injector bore.

Important: DO NOT crank the engine in order to expel any solvent from the cylinder. Cranking the engine with the injector removed may cause the injector sleeve to unseat and fill the cylinder with engine coolant.

9. Inspect the injector bore for any deposits and repeat brushing if necessary.

1. If the fuel injector sleeve was pulled from the cylinder head when removing the injector(s), refer to Fuel Injector Nozzle Tube Sleeve Replacement in Engine Mechanical - 6.6L.
2. Install a NEW O-ring onto the fuel injector(s).
3. Lubricate the O-ring with clean engine oil.
4. Install a NEW copper washer into the fuel injector bore in the cylinder head.
5. Install the fuel injector with injector bracket.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

6. Install the injector bracket bolt.

Tighten
Tighten the bolt to 50 N·m (37 lb ft).




7. Install the return pipe assembly.
8. Install the fuel injector return line to injector eye bolts and washers. Lubricate the washers with diesel fuel prior to installing.

Tighten
Tighten the fuel injector line to injector eye bolts to 16 N·m (12 lb ft).

9. Install the fuel injector return line to cylinder head eye bolts and washers. Lubricate the washers with diesel fuel prior to installing.

Tighten
Tighten the fuel injector return line to cylinder head eye bolts to 17 N·m (12 lb ft).

10. Install the lower valve cover. Refer to Valve Rocker Arm Cover Replacement - Lower Left Side or Valve Rocker Arm Cover Replacement - Lower Right Side in Engine Mechanical - 6.6L.