In some FIAT MAREA models, a series of repetitive symptoms become evident:

The engine is difficult to start, especially from cold. There is also an abnormal noise from the pre-control pump.

After several diagnostics of the incident, it was determined that it is caused by a displacement of the O-ring that is located between the filter body and the bottom cover of the pump set. This displacement is caused by excessive fuel pressure, and in many cases it can result in a leak in the fuel supply circuit.

To correctly repair the fault, take the following steps:


1- Firstly, the battery negative must be disconnected and the fuel tank cap removed and the pressure generated inside released. 

2- Cut off the pre-control pump power supply and re-connect the battery negative. 

3 - Then, start the vehicle and allow it to stop by itself and repeat the process until it is impossible to start the engine.

4 - Disconnect the battery negative.

5 - Remove the fuel pre-control pump set with care, be especially careful not to spill fuel in the vehicle and not twist the fuel level measuring arm. 

6 - Position the pump with the outlet downwards to empty any possible fuel residue there could be inside using a suitable container.



7 - Separate the bottom of the pump set with care so as not to break the fastening tabs and remove the O-ring.

8 - Use the special kit for the optimal replacement of the O-ring.

9 - Fit the correct spacer for this operation and properly fasten it.

10 - Insert the new O-ring and fit the pump set and confirm that the gauge arm rod is correctly positioned, between 0 and 5. mm.

11 - Fit the remaining elements in the reverse order and carry out a check to ensure that everything is working as it should.

NOTE: Remember that disconnecting the battery resets all the radio and navigation data, try to save all the stored settings in these two components before disconnection.