06 chevy 3500 diesel 6.6 cranks but will not start

new here, hoping for smart person. i am at a shop and had a chevy truck in last wk for f/f. filter was not filled before installing. lost prime. after getting it filled and running sent down the road. came back on roll back.forgot to mention primer wouldnt work 1st time .as in this time. got new filter heater housing and got it to prime. still will not crank. no codes,have a solus scan tool and found some funny readings fpr ,tc vanesposition fuel pressure,among other readings. this is the first duramax eng i have delt with in this situation. had a ficm and tried it(knew it wouldnt work but the boss wanted me to try it ) am gonna ck tomorrow for responce. am 30yr plus tech so have ck about everything i can think of only problem is i dodnt understand about fuel pressure test have not got the kit(j45873-30) as described in aldata test procedures. scan tool is snap-on so can get readings. concerns are can a crank sensor cause this without code? frp sensor cause a no crank,desired 40 actual 1 . tcvane position at 20% desired 0%. read about ckin place for metal debri in line from ful pump? i think sys ran dry and damage to inj pump is poss poss turbo any good help please.