Injector rebuild and black smoke

[masterslamma]

Hi,
i got a 2003 Connect 1.8 tdci 90hp with 200k miles on the clock.

In the last days it started to smoke heavy black as soon as the turbo builds up pressure. So from about 2000rpm on under full throttle you see black smoke in the rear mirror. While driving with constant speed there is no visiable smoke. At idle also no smoke, but the smell of the car from the outside has become much more than usual even there is no smoke. Got the to do the MOT next week by the way.

Forscan only says one EGR Falut, but my EGR is blocked anyway. But maybe the ecu tries to correct here something. Not sure.

I also did a leadback Test that showes, that #4 Injector has 2-3 times the ammount of leakback than injectors 1-3. Can the injector be the reason?

Also i checked for any vakuum or turbo pipe leaks visually but all seemed to be okay.

Its only the smoke while going full throttle, otherwise the engine runs completele fine, runs smooth, good power, good mpg but i has something has changed to the worse.

Could someone please point me into a direktion what i should check next. Do you think #4 Injector is the reason?

Thanks alot