Maxxforce 10

If your pump deadheads good pull that valve cover, disconnect all injectors and crank while checking for oil leakage. If excessive replace o-rings on oil manifold and retry, definitely looks like a blown out o-ring.

 

I didn't have time to get around it today. But I did go to the international dealer and I spoke to the service guy, which was friendly /most dealers don't want to help or give any info out.
He said at low idle, low oil pump should be
At 31 psi.. he said, while cranking and building 22 psi isn't to far off.
Hpop should be getting supplied unless there's an internal leak.
He also mention energizing the IPR with one wire to 12 volts second wire to ground, this give open loop for the pump work at its Maximum pressure.. luckily, I have a extra pig for the IPR laying around.
There a sensor on the back housing of the reservoir near pump. I will stick a manual on while testing, to get a reading. And having a second gauge on the out pressure side.