Need help LLY wont start

So its kind of a long story. I store my truck for the winter. Its a 2004.5 GMC Sierra. It has a Bully Dog GT programmer, a Airdog 165, an AFE intake and a 5in exhaust.This winter I decided to pull the batteries to keep them on a trickle chargers. Last month reinstalled the batteries and my truck fired right up without hesitation. I let it idle for 15-20 mins then tried to drive it, pulled it out on the road and it died. Cranks but wont start. Thats where my fun begins. I have no lights on or blown fuses, the only code I have is for a #8 glow plug. At first I thought was air in the fuel system, opened the bleeder plenty of fuel no air. Next I changed all three filters. Nothing. Removed the tune. Nothing. Thought maybe it was the crank sensor so I replaced that. Nothing. Seen a couple grounds that looked like crap. Cleaned those up. Still nothing. Took it to the dealer but my bully dog has the ecm locked so they couldnt do anything. The tech told me to reset the anti-theft. I thought for sure that was it makes sense. Read a couple forums reset it by key on for 10 min off for 10 sec for 3 times. And tried leaving the key on for 30 mins. Nothing. :bang:bang
So if anyone can give me any help I would greatly appreciate it

Will it start n die right away? Try priming it with the button? Could be your FICM possibly too

No it doesnt even try to fire. And yes Ive tried that too. Would the FICM throw a code if it goes bad?

Not always.

Do you have a way of reading rail pressure? It needs to see a certain amount before it will fire injectors

Any codes? If no codes then it is mechanical. I'm guessing rail pressure as well. Desired will be around 4500psi and it'll take about 1500+psi to fire it.

Don't try starting fluid unless disconnecting glow plugs first. Starting fluid will only tell you if it's getting air and has compression so a poor test.

No I have no way to test fuel pressure. I have disconnected the glow plugs and it will fire off starting fluid but will no stay running. Is there anyway to unlock the ecm without paying the $250 bully dog wants to unlock it?

The very bottom of the barrel scanners with a data stream can give you rail pressure. Get one, find out what your rail is at. Theft system would allow it to start for a few seconds then die. Since you have a lift pump you can kinda sorta rule our an air suction problem.

Once it lights off can you keep it running with "gas" pedal?

Without any data info, I'm gonna guess fuel rail relief valve, weak cp3 or big return rates on the sticks.

So today I only had a couple minutes to work on. I located a schrader valve on the fuel line coming from the FICM. While I was cranking it I had my dad push on it and it didnt seem to have but a couple pounds of pressure behind it. This week Im going to barrow a scanner from a guy I work with to take an accurate fuel rail pressure reading.