7.3 no start or long crank to start

I have a 99 F250 7.3. We bought a new service truck so @ 488,000 miles we took this one out of service. She was running great but had a massive oil leak at the oil cooler and it sat for 1-1.5 year or so till I finally got around to rebuilding the oil cooler. Since then sometimes it will fire right up but most times it will just crank and crank and no start. I've put new o-ring kits on all the injectors, new glow plugs, new IPR, new cam sensor, new ICP, two new batteries and new starter, I am wondering if it is a wiring issue or intermittent ground or something. When she starts she runs great, idles smooth, tons of power and drives great. You can run it for an hour, shut it off and immediately twist the key to start it back up and most times it is a no start again. I also bought one of those OBII readers but it does not seem to read anything when cranking, anyone had a similar experience? this is frustrating the hell out of me. I do have forscan and it shows zero codes

It may be possible the glow plus relay is weak. I had a similar issue that it would take a long time to start especially when cold outside. Evidentially the relays will slowly fail over time. Just a suggestion.