i have a 1998.5 cummins. I just installed 120 hp injectors (brand new) and the truck was starting fantastic even below 0 Celsius without any issues. Yesterday I decided it was time to adjust the valves. So I pulled off the valve cover and adjusted the intake to .008 and the exhaust to .018 (the truck was hot) now i have to turn it over at least 7-10 times for it to start. Possible the valves are too tight? or is there another issue that just happened at the same time?

I dont know how to add a signature but in case your wondering my truck has:
-hx40 turbo
-5" tb exhaust
-s&b intake
-edge ez
-fp, egt, boost and trans temp gauges
-fass 150gph lift pump
-125 hp injectors

EDIT** before the injectors it was hard starting as well, but it still fired up first try if plugged in.

 

Im no pro but i thought that motor had to be adjusted cold, and at a spec of .010 on the intake and 0.20 on exhaust. If i'm right your valves are way way too tight