crank but no start

[jmahan]

i have a 1996 7.3, it has 277,000 miles on it, ive changed the injector o rings and changed a few glow plugs then the truck ran realy good but after a month started losing power like no get up and go got realy hard to start and now it wont start, i changed the batteries starter and battery cables because it wasnt turning over right after that turned over like a new truck but wont start, changed cam position sensor, glow plug relay, starter relay, im guessing its the hpop but not 100% sure, i did notice there is oil in the valley pan and cant see where its coming from, could the hpop be my problem, i could realy use some help and input on my situation before i go and purchase parts so im not buying parts that arnt going to fix the problem, any input would be greatly appreciated. Thanks.

[CHUCK]

when cranking, any smoke? Are you getting wait to start light when you turn th ekey on?

[jmahan]

some white smoke but not alot, and the wait to start light comes on but it seems like it doesnt stay on very long,im not sure if its because its a little older truck but my work truck is a 99 f450 with a 7.3 and it stays on longer then my 96

[CHUCK]

mmmmm....... check the IPR valve, in the backside of the HPOP. The tin nut may have backed off. Other than that, I aint coming up with anything. Need to get it to somewhere that can run a few test, maybe check the psi on the HPOP.
Good Luck, keep us updated