Originally Posted by F350-6

This is your problem. Unless you've got a mechanical gauge on there, then you cannot trust any readings your scanner gives you after the ICP is unplugged. If you've really only got 140 psi of ICP, then your injectors won't fire. You need to find your high pressure oil leak. You need 500 psi min. for the injectors to fire.

Assuming the engine oil is full and the newer IPR is working, have you checked the wiring on the IPR to make sure it's not chaffed or the insulation isn't brittle? Can you monitor IPR duty % while cranking? Is there any oil in the bottom of your fuel filter bowl?

If you've got the parts, stick a 3,000 psi gauge in one head and block off the high pressure oil line to the other head. See what kind of pressure you get while cranking. Keep in mind it may start on only one bank, so if you don't want it firing up on half the cylinders disconnect the CPS or pull a fuse. If one bank builds pressure and the other does not, time for injector o-rings.