Black smoke

My astra 1.9cdti design 150bhp 16v has a lot of black smoke on start up and under accelleration, am worried its the manifold, the egr has been cleaned and blanked off, dpf removed, and has had a remap and bypassed dpf/egr because of the limp mode but the smoke is imbarresing, I cant see any split pipes but they can be hard to see unless under pressure so could of missed 1, I understand not enough air getting thru so air filter replaced, will replace oil again and filter but was done 1200miles ago, and will replace fuel filter, have been told to check MAS sensor and clean it, is there anything else I can check and any instructions, thanks daz