I have a 2000 HD with 6.5 turbo that ran fine before we let it set up for a year. It is now hard to start and now blows out white smoke. The filters and fuel were changed. We even change the injectors. The only code is p0216 (injector timing). We drove it a few miles it smokes and runs very bad. It won't hardly pull itself. The pump is hid under the intake and I don't have a brakedown on this motor.
Sounds like an injector let go. Loosen one injector line at a time, until the engine starts to shake, then tighten the line back up. Keep doing it until it quits blowing white smoke, or makes less of it. That'll tell ya what injector(s) have gone out.