How long have you cranked the engine to try and start?
Ok then you have one of two things going on either the IPR valve is not working correctly or you have a leak somewhere in the high pressure oil system. The way to test the high pressure system for a leak on this year is to remove the valve covers and install plug in the oil supply line a monitor the ICP while cranking.
I have to run out for about a hour I will give you more information when I return.
I am not sure which one the IPR valve is but I did replace the sensor that cost $360 but not the one that is $150 as I looked like it had been replaced not to long ago.
When I replace the high pressure pump I unbolted the pipe on top and rotated it 180 degrees out of the way, removed the old pump, placed the new pump and rotated the pipe back on top. I did not try to remove the pipe so not to creat any type of leak. The one thing that just came to mind is that I had an error P0670 after replacing the pump. I found that I did not plug one of the connectors completely in at the control module at the top right side of the motor. I have corrected that problem and I no longer has the P0670 error. Maybe this information may lead you closer to what the problem maybe. I will look for your responce when you get back.
Do you have access to a scanner that is capable of monitoring sensor data?
The IPR is the regulator, it is the larger one that screws into the pump.
Is there a priming process that I need to go through after I replace the high-pressure oil pump?
Just normal cranking of the engine is how you prime the system. It usually takes a solid 2 to 3 minutes of cranking for it to start. In 30 to 40 second intervals to prevent overheating of the starter.
Usually after you see the oil pressure gauge come up on the dash it takes about another 1 to 2 minutes to build high pressure oil.