1-I guess if I had a test stand and planned to put the IP on my truck I would try some runs with the truck injectors (on the stand). Unless I was paying for test time. Comment only because of noted stand/truck difference.
2-Are delivery valves just check valves and don't need balancing?
Is post POP line pressure "set" by injector and POP pressure curves?
If line pressure leaks past pintle before/after POP which increases with IP/injector temp , then cranking below some critical speed (different everyone based on above) will not attain POP, no injection, no smoke. Not just retarded, nothing.
Is shutdown due to blocked returns a safety feature, somehow, or just consequence of no return springs for dual plungers? Anyone try adding return springs?
Can Leaking return lines drain injection lines meaning long cranking?
Air before IP causes stall when it reaches where in the IP, transfer pump, dual plungers? After stall, governor housing should still be full of fuel like after normal run/shutdown. Transfer pump with air. Air anywhere else in IP? Above recap, I hope, mainly to consolidate my thinking @ IP operation