High Pressure Fuel Lines

HIGH PRESSURE FUEL LINES

High-pressure lines are used between the fuel injection pump and the fuel injectors only. All high-pressure fuel lines are of the same length and inside diameter. Correct high-pressure fuel line usage and installation is critical to smooth engine operation.

Whenever the high-pressure lines are removed, they should be removed as a bundle (if possible) They should also be tagged for return to original position.

Warning: Use extreme caution when inspecting for high-pressure fuel leaks. Inspect for high-pressure fuel leaks with a sheet of cardboard. High fuel injection pressure can cause personal injury if contact is made with the skin.

CAUTION: The high-pressure fuel lines must be clamped securely in place in the holders. The lines cannot contact each other or other components. Do not attempt to weld high-pressure fuel lines or to repair lines that are damaged. Only use the recommended lines when replacement of high- pressure fuel line is necessary

REMOVAL

CAUTION: Cleanliness cannot be overemphasized when handling or replacing diesel fuel system components. This especially includes the fuel injectors, high-pressure fuel lines and fuel injection pump. Very tight tolerances are used with these parts. Dirt contamination could cause rapid part wear and possible plugging of fuel injector nozzle tip holes. This in turn could lead to possible engine misfire. Always wash/clean any fuel system component thoroughly before disassembly and then air dry. Cap or cover any open part after disassembly. Before assembly, examine each part for dirt, grease or other contaminants and clean if necessary. When installing new parts, lubricate them with clean engine oil or clean diesel fuel only.

1. Disconnect both negative battery cables from both batteries. Cover and isolate ends of cables.
2. Thoroughly clean fuel lines at cylinder head and injection pump ends.





3. Remove cable cover. Cable cover is attached with 2 Phillips screws, 2 plastic retention clips and 2 push tabs. Remove 2 Phillips screws and carefully pry out 2 retention clips. After clip removal, push rearward on front tab, and upward on lower tab for cover removal. Do not remove any cables at lever.





4. Disconnect wiring harness (clip) at bottom of Accelerator Pedal Position Sensor (APPS) mounting bracket.





5. Using 2 small screwdrivers, pry front wiring clip from cable bracket housing. Position wiring harness towards front of engine.





6. Remove electrical connector from APPS by pushing connector tab rearward while pulling down on connector.





7. Disconnect 2 electrical cables from cable mounting studs at intake air heater on top of intake manifold.
8. Remove engine oil dipstick from engine.
9. Remove engine oil dipstick tube support mounting bolt and position tube to side.
10. Disconnect clamps and remove air tube.





11. Remove 4 air intake housing mounting bolts and remove housing. Position ground cable at top of air intake housing to front of engine.





12. Remove intake manifold air heater element block from engine. Discard old upper and lower gaskets

13. Remove 3 cable bracket housing mountmg bolts. Carefully position cable bracket and cable assembly to side of engine. Leave cables connected to lever.





14. Remove engine lifting bracket at rear of intake manifold (2 bolts).
15. Remove bolts from all fuel injection line support brackets at intake manifold.
16. Place shop towels around fuel lines at fuel injectors. Do not allow fuel to drip down side of engine

CAUTION: When loosening or tightening high-pressure fittings at injection pump, use a back-up wrench on delivery valve at pump. Do not allow delivery valve to rotate.





17. Loosen high-pressure lines at injection pump beginning with cylinders 1, 2 and 4.
18. Loosen high-pressure lines at cylinder head for cylinders 1, 2 and 4.
19. Carefully remove front line bundle from engine. Do not bend lines while removing. While removing front line