Cm871 pouring blue smoke out exhaust up hill. Please help

[EdgarLeyva]

Recently purchased a 2010 t660 with a cm871
Prior owner did tons of work just 2 months ago including the following
Overhaul, new head, new turbo & actuator, new egr valve and cooler and more but not in reference to the engine.
Started driving it and the second day i was in it, it started pouring out blue smoke out of the exhaust when climbing a hill or on-ramp mainly when loaded.
I have done the following thinking it would fix the issue:
Egr tune up including: new delta p sensor, new imap sensor, new exhaust back pressure sensor, new dozer injector, new dpf temp sensors, had the doc and dpf cleaned.
To add to this my truck is only getting 4-5mpgs.

Today i unplugged the dozer injector and waalaa no more smoke.
I know this is incorrect. But how or what should i do next to fix the problem.
Thanks in advace for the help guys.