Hyundai Getz Crdi 2008 problem

My Hyundai Getz Crdi 2008 (64,000 km) has begun to fail during the first ignition, since it starts for a few seconds and stops. The first time I had to take it to an authorized workshop where they told me that it was air in the injection system and that it was not frequent. I have four more and more on. The last three times I have pressed a rubber pear that is at the entrance of the fuel filter and I have managed to turn it on, I do not know if it will be the right thing but that is not the idea of ​​how it should work. What could be the drama?

Hello, the problem can be in the oil filter or in the pressure regulator which is at one end of the pressure accumulator tube this has a micro filter on the tip which is optimated and produced that fault.