M816 wrecker fuel pump problems

After running my engine for a short while I stopped and came to restart it but would not start. No smoke from exhaust when cranking . Is there an electrical solenoid that stops the diesel which in my opinion seems to be the issue ? 1970 Cummins engine . Is there anyone who could help ? I live in Bucks in the UK

can anyone tell me if there is a lift pump on the fuel pump or if there is a bleed screw ? Many thanks in advance!

This video describes the Solenoid. What it doesn't mention is the big screw in the middle of the valve. This is to make the solenoid fully manual. There's a knob on the outside of the pump. Screw it all the way in to bypass the solenoid.

Have you downloaded the TM's for the truck? They would help answer your questions.