1996 Chevy K1500 6.5L running rough and white smoke
 

I got a 1996 Chevy K1500 with the 6.5L Turbo Diesel.Awhile back the starter went out and it sat for a few months.After the new starter was put on the truck was running very rough and is white smoking on idle and gets much worse when u try to drive it or throttle up.I have put about 15 gallons of fresh fuel in it,changed the fuel filter,put in 8 new injectors,rebuilt the turbo and changed oil.Nothing has helped.I'm at a loss cause it ran like a top with no smoke before the starter went out.Any ideas?

Also it seems to be drinking fuel like crazy and the passenger side exhaust manifold looks wet but there isn't a fuel leak that I can see.

Head gasket?
Bad new injector?

I thought about the head gasket but it isn't using and water and it couldn't have blown a head gasket not running those few months.