Problems with a Diesel Pallium

Hello people, I have a problem with a diesel canopy, the engine goes from a thousand wonders, regulating does not appear any problem and accelerating less, but when I turn on the A/C it loses a lot of power, regulating the escape gives the snatch of being in three cylinders and noticing that long black smoke due to times. Zondie valves and are fine, I don't see wear on the cams, what I would like to know if it is due to an injector or a attractive in the injection pump?
Thank you very much !!