Bleeding Air from the Fuel System

If the fuel tank has been completely run dry or if any fuel system components have been replaced, bleeding air from the system is generally not required, as it is bled automatically during engine start-up.

If starting difficulties occur, check whether fuel is reaching the injectors. To do this, loosen the union nuts on two injectors and crank the engine without preheating until fuel reaches the union nuts. Tighten the nuts to 20 N·m and start the engine again.

* If air is not bled from the fuel system automatically, proceed as follows:

PROCEDURE
1. When working on the fuel system, observe the cleanliness requirements given in the section Cleanliness Requirements When Working on the Fuel System.
2. Make sure diesel fuel does not get onto the coolant hoses. If fuel gets on them, wipe the hose immediately. Hoses damaged by diesel fuel must be replaced.
3. Disconnect the supply line (3) to the injection pump from the fuel filter. Squeeze the clamp while doing so. Collect the leaking fuel and dispose of it. Refer to the accompanying illustration.

4. Insert a hose into the connecting thread and lower it into a container.
5. Disconnect the fuel supply pump relay and jumper the terminals on the relay base. The pump may start running. Refer to the section Checking the Fuel Pump Relay.
6. If fuel flows out of the connection, remove the jumper and reinstall the relay.
7. Reconnect the hose, first lubricating the seals with petroleum jelly or acid-free grease. Replace damaged seals. Secure the connection with the clamp.
8. Unscrew the threaded plug (1) on the injection pump by two turns.

9. Crank the engine with the starter so that fuel emerges from the threaded plug. Collect the leaking fuel.
10. Tighten the threaded plug (1) to 25 N·m.
11. Remove the intake manifold covers by unscrewing the mounting bolts. Refer to the accompanying illustration.

12. Loosen all injector union nuts using a special tool, such as HAZET 4550. Crank the engine with the starter until fuel emerges. Then tighten the nuts to 20 N·m. If leaks occur, retighten them to 25 N·m. This is the fastest way to bleed air from the fuel system.
13. Thoroughly collect the leaking fuel in the engine compartment.
14. Reinstall the engine covers.