TURBO DIESEL ENGINE RENAULT LAGUNA 1.9 99`

I present my case:
I was walking with my Renault Laguna Turbo Diesel 1.9 99 'and suddenly went out as if I had turned the key to put out (he kept rolling). I tried to start, the engine revolved but it didn't turn on ... then (1 minute later) turned on, I made 100 meters more and the same thing happened again: from there I could not start it anymore.

A mechanic told me that it came out (because it was lazy) the gear of the injection pump is possible? Would you have to have done some abnormal noise? Well, I don't hear anything ... and then, already at home, every time I tried to start the starter, it was all normal noise, only the engine did not start. The curious fact is that I stop, I could make it start and make 100mts more, and it came back ...

On the other hand, the gear of the injection pump goes with the distribution strap or with that of the air conditioning? Because he says that is why the engine stays out of his point, and that there is now a problem with the valves.

I await your comments, thank you.