Cummins ISL High pressure fuel pump

[MOFIRE]

I am working on a 2011 Cummins ISL with 42,000 miles in a fire truck. This truck has set for a few years from being wrecked.
It ran when I parked it. It will not start now. I can get fuel out the top of the pump from the the electric pump. It will not pump out of the high pressure outlet while cranking. I pulled the head off the pump and everything looks good. I have read about a check valve in the high pressure side but have not located it. Does anyone know where this is located or may some suggestions on what the issue might be. Next move for me will be to change the complete pump out.

[Rawze]

if you register your engine ser# on quickserv.com you can get all drawings and procedures.. its free.