I have a 03 F-450 with a 7.3 power stroke engine. When the truck is hot and I shut it off it will not start until it cools off about 30 minutes. The truck runs fine after starting. The computer code came up # 8 injector. I replaced injector and all new o rings in all the other injectors. The truck is also losing about 2 ouarts of oil and there are no leaks on motor but there is oil in the turbo.What could it be?

Your turbo is likely toast, due to wear (oil failure). Turbos and conventional oil don't go together well--they can't take the heat, especially after the engine is turned off, heat builds, and the turbo keeps spinning for several minutes at 50,000 rpm. With conventional oil, it's only a matter of time until the turbo goes. As the oil level drops in PSDs, so does the fuel pressure. Oil needs to be filled to the "FULL" line, not just to protect the engine but also for maximum fuel pressure. This is very important. Two quarts low is huge. Read the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-8.html#post1415281

Once you replace the turbo, start using one of the full-synthetic diesel HDEOs recommended in the link, along with an Amsoil Ea filter. Better, yet, use the Amsoil Ea filter along with a by-pass filter--this makes it very cost effective. After that perform regular used oil analysis (UOAs).

As far as your no start. Pay attention to your tach when you are cranking and see if it is registering any rpms. I have seen many a crank sensor fail when hot cause this. If the tach is stuck at 0 rpm, that is where I would start on the Powerstroke.