New 1000 Serie » How to eliminate air from the fuel system

Warning! If your skin comes into contact with high-pressure fuel, obtain medical assistance immediately.

If air enters the fuel system, it must be removed before the engine can be started.

Air can enter the system if:

1. The fuel tank is drained during normal operation
2. The low-pressure fuel pipes are disconnected
3. A part of the low-pressure fuel system leaks during engine operation.

In order to eliminate air from the fuel system, proceed as follows: Vent screws are not fitted to the fuel injection pump. Air will usually be removed from the fuel pump automatically.

Caution: If the fuel system is empty or if the canister(s) of the fuel filter have been renewed, it will be necessary to eliminate air from the fuel system, especially the fuel injection pump.

1. Loosen the vent plug on the filter head of the pre-filter (A2). Operate the priming lever of the fuel lift pump (B) until fuel, free of air, comes from the vent plug. Tighten the vent plug.

Note: If the drive cam of the fuel lift pump is at the point of maximum lift, it will not be possible to operate the priming lever. In this situation, the crankshaft must be rotated one revolution.

Loosen the vent screw (A1) on the main filter. Operate the priming lever of the fuel lift pump until fuel, free of air, comes from the banjo bolt. Tighten the vent screw.

For filters with a separate element: Loosen the vent plug (C1) or banjo bolt on the top of the filter head.

2. Operate the priming lever of the fuel lift pump (B) until fuel, free of air, comes from the banjo bolt or vent plug. Tighten the banjo bolt or vent plug.

Caution: Use a spanner to prevent movement of the fuelled starting aid (D1) when the union nut (D2) is loosened or tightened.

3. Loosen the union nut (D2) at the fuelled starting aid and operate the priming lever of the fuel lift pump until fuel, free of air, comes from the connection. Tighten the union nut at the starting aid.

Note: For Delphi fuel injection pumps: Loosen the union nut at the outlet connection of the low pressure fuel leak off pipe which is on top of the governor housing of the fuel injection pump. Operate the priming lever of the fuel lift pump until fuel, free of air, comes from the connection. Tighten the union nut.

Caution: Do not tighten the union nuts of the high-pressure pipes more than the recommended torque tension. If there is a leakage from the union nut, ensure that the pipe is correctly aligned with the atomiser inlet. Do not tighten the atomiser union nut more, as this can cause a restriction at the end of the pipe. This can affect the fuel delivery.

4. Loosen the high-pressure connections at two of the atomisers (E1).

Caution: Damage to the fuel injection pump, battery and starter motor can occur if the starter motor is used excessively to eliminate air from the fuel system.

5. Put the electrical system switch to the "On" position. Ensure that the manual stop control, if one is fitted, is in the "Run" position. Operate the starter motor until fuel, free from air, comes from the pipe connections. Tighten the high-pressure pipe connections to 27 Nm (20 lbf ft) 2,8 kgf m. Return the switch to the "Off" position.
6. The engine is now ready to start.

Caution: Operate the engine at low idle speed for a minimum of two minutes immediately after air has been removed from the fuel system. This will ensure that the pump is free of air and prevent any damage to the pumps internal parts by metal to metal contact.

If the engine runs correctly for a short time and then stops or runs roughly, check for air in the fuel system. If there is air in the fuel system, there is probably a leakage in the low pressure system.