Black Smoke Problem Landcruiser Colerado 96

Can anybody offer advise. I had white smoke and found a crack in the cylinder head (3.0TD)changed it and have had black smoke ever since. It goes well but get smoke when you accelerate hard from pulling away or slowing down (at junctions) and re-accelerating. The Toyota garage has not been able to fix it yet. Any suggetions (they have checked all hoses, injectors, timing etc.

Any suggestions greatfully received