Hello everyone. Recently picked up a nice 06 250. Well maintained, 2 owner with 195k. New to the diesel world but mechanically inclined. Did the usual rotella t6, new motorcraft oil & fuel filters, blue spring, coolant flush new rotella elc, egr delete. Truck has been running & driving great. Picked up a sct x4 & loaded the tow 50 tune, drove it around for a day. Uploaded the tow 65 the next morning & truck wouldn't fire. Returned it to stock & the same. Thought maybe it was the batteries (new in December) so pulled them both & charged overnight. Swapped them the next morning & still won't start. It had given me 0 issues, stated great cold or hot & now not at all. Volts are 12.5 koeo, ficm 48, ipr jumps to 85%, icp only goes up to 375psi. Rpms while cranking were around 200. Don't know if the sct or standpipes/dummy plugs have been addressed or not. The turbo lines have the 07 updates but no idea about the rest. Where do I need to start? I think the tuner is coincidental but maybe I'm wrong? Trying to research, seems it could be very minor or major. It's strange to me as it gave no signs at all.