Diesels are pretty simple machines, if they get fuel they will run. Give them more fuel then fully burns you get smoke, give them to little and they don't run very well and low power and no smoke.
Your issue sounds like not enough fuel. Start with the fuel filter, dump the contents into a clear...
Is the arrow on the bulb facing toward the filter?
Are you sure the bulb works?
Also do the fuel valves installed have check valves in them? Normally the pointer on the valve points toward the motor not the Tee or filter
I cannot read the pic, print is to small.
With it that low need to test fuel pump and regulator. Can place a valve on the line going back to the fuel filter and with pressure gauge on the rail start closing off the valve slowly. Turn the key off/on to have the pump cycle. If you get up to 50...
Have you felt around on the cooler? I have one just like it on the shelf with a 1/4 plug on the bottom of one end.
If you have room you could put in one of these p/n 861505
It's feasible but not recommended. Folks in south Texas woke up one day with temps way below what they have ever seen before.
Need full strength RV antifreeze to protect or no water at all. If you pour real antifreeze into the hose it will mix with the water and have better protection, but...