lossing power under load and blue smoke

evening,, anyone got any ideas?? I am losing power under load and smoking blue smoke,, this started when I was running on bio, I have run line cleaner + £100 worth of diesel, checked the fuel line for poss air leak, new fuel pump, replaced turbo pipes, turbo is kicking in bout 1200, new diesel, air, oil filter.. not noticeable losing oil or water,, seams to be using a lot of fuel and not really getting anywhere up hill fast... well at the speed it normally does,,, Im stumped?? anyone ???

cheers keef

disco 300tdi