Lift pump kicking out.. possible plugged line?

[Bullrider9]

I’ve read a lot of threads, but was unable to find much info, on my current problem.. yesterday, my 2014 ecodiesel shut off while idling. I turned the key off, then put my foot on the break, and started it. It started up immediately… then about an hour later, it did the exact same thing. And about 30 minutes later, it did it again, but this time it just turned over and wouldn’t start. I then noticed that my lift pump was not turning on, when the ignition was turned on… so I checked the wiring, and voltage was all acceptable. So I lifted the fuel pump out of the tank (through the hole I put in the box). And I wiggled all the connections, and tried plugging it back in. I then engaged the pump, using AlfaOBD… and it worked fine. I then connected the lines, and tried engaging it again… it only tried for a split second, and quit. So I took pump out, wiggled connections, and replaced in tank securely. And engaging the pump worked again.. but as soon as I connected the output line, it would try for a split second, then quit. I worked my way down the line, disconnecting at fuel filter, then the hpfp, with same conclusion… if the line is on, then the pump kicks out. But If it’s disconnected, it will keep pumping. I thought any excess fuel, was looped back to the tank… but that’s not happening. Is it possible that there is a clogged line, and the fuel pump is kicking out, because the ecm is reading too high of pressure? Or is the pump the problem.

I do NOT have any pressure gauges, to check actual fuel pressures. But I do have alphaOBD, as well as an autel MK808, that read rail pressure.

sorry for the long post.. just wanted to make sure I laid out all the details. Thanks in advance!