What is inside the HPOP reservoir? Is the anti drain valve in there? is it easy to check if I just pull the HPOP cover off?

I'm still having intermittent issues of the HPOP draining after a day or so of not driving.

 

What happens when this anti-drain valve doesn't work? I'm having a problem when my truck sits for more than 10 hours - it starts fine and runs for about 30 seconds , then shuts down as if it ran out of gas. After turning it over for about 45 seconds, it starts back up, runs really rough, then smooths out and is fine all day until it sits again over night. I don't know if it's the fuel pump or the HPOP.

 

Sounds just like mine. Except mine doesn't do it all the time...

The HPOP reservoir is filled from the regular oil pump. The reservoir needs to stay full since it feeds oil to the HPOP which in turn fires the injectors. If it drains there is no oil to fire the injectors except for that initial crank because there is already oil in the HPOP.

Mine has left me stranded a few times. I had to get it towed the last time. The shop stuck the computer on it as the batteries charged. He checked everything as he tried to crank. All he saw that was wrong was no injection control pressure. Once that came up to where it needed to be the truck cranked and ran fine.

I'm waffling between the reservoir draining or the injection pressure regulator being bad (even though it has a new one in there)

 

Thanks for the info - mine goes to the shop tonight - I hope it's simple - I just want it fixed - I use mine as a daily driver and I need it.