Section 35.7 High Pressure Lines

Section 35.7
High Pressure Lines

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 1. High Pressure Pump‪

 4. Fuel Rail‪

 2. Low Pressure Pump‪

 5. High Power Fuel Lines from Pump to Rail‪

 3. High Pressure Fuel Lines from Rail to Injector‪


The fuel is compressed by the by the high pressure fuel pump and is sent to the two high pressure lines and then to the fuel rail. The fuel then goes from the rail through the individual high pressure lines to each injector.‪

Section 35.7.1
Removal of High Pressure Lines

Remove as follows:‪



To avoid injury to eye or face, wear a face shield or goggles when conducting a pressure test.‪



To prevent the escape of high pressure fuel that can penetrate skin, ensure the engine has been shut down for a minimum of 10 minutes before servicing any component within the high pressure circuit. Residual high fuel pressure may be present within the circuit.‪

Note: If removing a fuel line from cylinder #1, remove the Intake Manifold Temperature Sensor from the intake manifold first and cover the hole.

  1. Disconnect batteries.
  2. Place shop towels under appropriate lines to absorb leaking fuel.
  3. Using tool J-48770 loosen injector high pressure line nuts at the fuel rail and camshaft frame and the pump lines at the fuel rail and at the pump.
  4. Remove the injector lines from the cam frame seal.
  5. Clean the line using compressed solvent and compressed shop air.

Section 35.7.2
Installation of High Pressure Lines

Install as follows:‪

  1. Using tool J-48770, torque the high pressure line nuts at the fuel rail and camshaft frame and/or at the fuel rail and pump to 40 N·m (29.5 lb·ft).
  2. Prime the system using the fuel priming valve or the hand primer. Refer to "6.5 Fuel System Priming" , “Fuel System Priming.”
  3. Start and bring the engine up to operating temperature (over 140°F/60°C).
  4. Run for a minimum of three minutes at 1800 rpm.
  5. Visually inspect the lines for leakage.
  6. If there are leaks, change the line.

DD15 Fuel System Technician's Guide - DDC-SVC-MAN-0037
Generated on 10-13-2008

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