If it's been plugged-in, I don't think it's a GP problem either.
Where did you spray the WD? Not into the Air Filter Snorkel - right? You took the lid off the filter housing and sprayed right into the tubing connected to the Turbo?
Happened? No "rattle"? No change in cranking speed? No indication that it was trying to run at All?
WOW! I'm not sure where to go from there! I mean, when doing this you're bypassing So Much. You don't need a Computer, IDM, HiPres Oil System, Diesel, Any Sensors, all it should take for a diesel to do to something
, to have Some Reaction, is Compression & Fuel/Air. And you gave it that!
If it ran fine before, I'm sure you've got enough compression.
I'm kinda stumped
,,,, Something's Wrong but it's not adding-up either.
As for Propane (and again, I think that's the majority of what WD does for you), it's not going to Blow-Up or anything
Just have somebody turn the key and increase the gas until something happens. BUT, my suggestion to try this was based on maybe getting fuel into the injection system and an aid to purging air there by saving the starter from having to do too much work. From what you describe now, that it never ran dry, this shouldn't be necessary...
Lets' go back to basics,
Warmed engine (plugged in you don't need good Plugs & Relay)
PCM is running (you get a WTS and it acts normal)
Tach rises (CPS is functioning)
Good cranking Speed (PCM is satisfied, as long as it sees ICP pressure 500psi & Voltage 10+ it should try to start)
Oil Level OK?
Plenty of fuel in the tank? (are you at 1/4 or below?)
Is there fuel in the fuel bowl now? Does it refill after cranking?
Look above the pass ft tire, you'll see a 3/8" metal tube, against the motor that ends there, it's the drain for the bowl (yellow lever you slide to the side). Get a cup, open the lever, drain the fuel bowl, look at the fuel, close the lever. Then, turn the key to the ON position (should hear the pump) for 15 secs. Drain the fuel bowl again, whaddya got?
Can you hear/feel the pump running (below the dr seat, against the framerail)
Is your truck "chipped"? If so, remove it as a Test.
Any white "smoke" (fuel vapor) at the tailpipe while cranking?