why would a 1986 mercedes 560sl be blowing black smoke out the tail pipe

Black smoke is usually fuel overload,gray is oil,white is water,your car is loading up on fuel,this can be caused by bad 02, sensor,s or catylac converter clogged,

Thanks T_S_T the guy thats working on it says he doesnt think its the catlac converter,he changed the fuel injector,had prob with it...we will see after its changed

i have 1986 560sl car start fine but when i go for a drive it dosnt have power and lot black smog caming tru tail pipe i already replace //new fuel injectors / fuel pump / all injectors seal /all vacuum hoses/ fuel presure regulator /oxigen sensors /fuul tunaup/ but styill running bad but when is idlin loock like is fine is not chaiking i realy dont know any help will be tank fuul