To check your ipr and hp oil system:
1. Get an ipr connector from Ford and put 2 long wires on the end, plug it into the ipr. Later you will attach the 2 long leads to b+ and negative ...... this will close the ipr.
2. Then remove your icp sensor (04.25 and up truck??) from the passenger side valve cover and thread a fitting in with an air fitting on the end (so you can apply compressed air to the hp oil system).
3. Remove your oil fill cap, your intake up to the turbo (get the ccv out of the valve cover at least), and the hot side cac tube.
4. Then, command the IPR closed for only 30 seconds, apply 100psi air to the hp oil system and listed to where the leak is coming from.
When you hear it you've found your problem....that is assuming you have a hp oil problem.
If your building low and high oil pressure fine, then you've just wasted your time.
Generally on no-start conditions that are related to "high pressure oil" leaks, the vehicle will still develop low pressure system pressures. However, the plug on the H.P. oil feed can occasionally blow out, the H.P. pump seal can blow out, and on the '03-04 trucks the ball on the side of the H.P. pump blow out - causing loss of base oil pressure.
taken from the 6.0 no start checklist on thedieselstop.com