Detroit Diesel — Installation of High Pressure Fuel Injector Lines
Repair & overhaul · High pressure fuel injector line and transfer tube
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Do not use pliers or sharp-edged tools to bend injector lines.
- Discard the old high pressure fuel line and transfer tube; do not re-use them.
- New high pressure fuel injector lines are supplied ready for installation.
- Do not re-torque high pressure fuel injector line nuts; if leaks are detected, install new parts.
- Do not loosen any high pressure fuel injector line nuts or other fuel line connections for priming; use the priming port on the fuel filter housing.
- Perform fuel system service in a well ventilated area to avoid exhaust fumes injury.
Procedure
- Ensure the damper is aligned correctly on the new high pressure fuel line; damper edge 16 mm from the first fuel line element edge.
- Apply a light coat of clean engine oil to the transfer tube O-ring and install the transfer tube into the cylinder head.
- Using a 24 mm socket, torque the thrust nut to 45 N·m (33 lb·ft).
- Align the new high pressure fuel injector line fittings to the transfer tube and unit pump; ensure correct orientation.
- Hand tighten the fuel injector line nut first at the unit pump, then at the transfer tube.
- Draw a vertical line with a highly visible marker along the front edge of both nuts and up the fuel line.
- Using a 17 mm wrench, tighten the fuel line nut at the unit pump end by turning it through 120 degrees.
- Hold the transfer tube thrust nut with a 24 mm wrench; tighten the fuel line nut at the transfer tube end through 120 degrees.
- Ensure all six dampers on the high pressure fuel injector lines are installed correctly and aligned vertically.
- Install the intake manifold.
- Install the cylinder head covers.
- Prime the fuel system (refer to Priming the Fuel System).
- Run the engine and check for leaks.
- Shut down the engine.
Tools required
- 24 mm fuel line wrench J-45063 or J-47484 Amazon
- 24 mm socket Amazon
- 17 mm fuel line wrench J-47483 Amazon
- 17 mm open end wrench Amazon
- highly visible marker Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Transfer tube thrust nut torque: 45 N·m (33 lb·ft)
- Fuel line nut turn at unit pump end: 120 degrees
- Fuel line nut turn at transfer tube end: 120 degrees
- Damper edge 16 mm from edge of first fuel line element
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.