I have a 2003 300TDi (RoW spec) - I was overseas and had a problem which at first felt as though the turbo had gone, the engine worked up until the turbo tried to kick in then it through out clouds of blue smoke. The mechanic in Yemen described it as a fuel return valve on the pump which had gone and he had it replaced - unfortunately they didn't give me the original back. Ever since then the car has been noticeablly slower - I know they didn't replace it with a genuine part and want to now do that as I'm back in the UK - does anyone have an idea what this may have been - I asked him where it was and he pointed to the fuel pump.
grateful for any ideas
I should say that the turbo is uprated along with the intercooler but don't think that afafcetd the part failing
D