Operations

OPERATIONS

0510C10 - FUEL SYSTEM - CHECK DELIVERY PRESSURE

1108

• Remove the throttle body cover (see PROCEDURES OP. 1056A30).

899   1108

1. Disconnect the fuel delivery pipe from the injector turret.
2. Connect a pressure gauge between the disconnected pipe and the fuel inlet connection to the injector turret.

• Open the tap A.
• Connect the diagnosis device, operate the fuel electropump through the procedure of the programme «Active diagnosis» and check that the pressure value on the pressure gauge is 1.1÷0.2 bar.

• Un excessive or insufficient value indicates the following failures:

• faulty fuel electropump;
• faulty pressure regulator;
• clogged fuel filter;
• clogged electropump fuel return circuit.

Operate as follows in order to detect and remove them:

Pressure under the prescribed value(<0.9 bar)
The fault can depend on: inefficient electropump, clogged fuel filter, not calibrated pressure regulator. Fasten the fuel return pipe in order to detect it.

a) If the pressure rises immediately to 0.9 bar or more, the pump is efficient and the filter is free, therefore the pressure regulator is faulty and must be replaced.

b) If the pressure does not rise immediately to 0.9 bar, the fault will not be found in the regulator, but in the clogged filter or in the clogged suction pipe (replace the filter and check the pipe) or if the fault remains, it is in the overworn electropump that will be replaced.

Pressure over the value prescribed (>1.2 bar)
The fault can depend on: not calibrated pressure regulator, clogged fuel return pipe. Remove the fuel return pipe from the injector turret and insert a provisional pipe ending in a tank .

a) If the pressure decreases to the normal value immediately, the damage is due to the clogged fuel return pipe that must be repaired or, if necessary, replaced.

b) If the pressure is still over the normal value, the damage is due to the pressure regulator that for this reason must be replaced.

Progressive and continual pressure drop stopping the function of the electropump with the pressure gauge tap closed and the fuel return pipe to the reservoir from the turret choked by the pliers provided for the purpose (do not damage the pipe).
This fault is due to the electroinjector seat that is not well tight and for this reason the cover must be replaced completely.

Progressive and continual pressure drop stopping the function of the electropump with the pressure gauge tap opened and the fuel return pipe to the reservoir from the turret choked by the pliers provided for the purpose(do not damage the pipe).
In this case, the fault is in the damaged antireturn valve, thus the complete electropump must be replaced.

• With fuel electropump activated, close the tap A of the pressure gauge and detect the higher pressure value reached.
• If the value does not exceed 1.9 bar replace the electropump.
• Disconnect the pressure gauge and reconnect the fuel delivery pipe to the injector turret

(Cont..)