mondeo diesel black smoke?

P reg diesel mondeo with endura engine produces excessive black smoke under accelleration and/or load (hill) occurs even with moderate accelleration. Have applied independant vacumn to exhaust gas regeneration valve accuator, this appears to have improved the situation whilst the vehicle is stationary. There is some improvement on road test but black smoke remains excessive. Any help would be much appreciated.

Bosie
March 2008