Something else, if you do get it to hit on one or more, stop cranking and let the glow plugs heat up a few times to get really hot, then crank again. It should take off running.
The 6.2/6.5 have a pick up pump very much like a sbc /bbc engine mounted in the same location as the gas engines. They go bad just like all the others, so check it for pressure or leaks.
Joe
