If you are getting
Crank -> Backfire BANG!
crank -> Start
its the cam sensor, recently unplugged or disconnected or bad or bad wiring etc...
If you are getting
cranking cranking cranking -> No start (no backfire)
Crank second time -> Starts quickly
Its probably the FA Cranking multiplier table
Increase the valves in the temperature range of starting (70*F here In florida) so double or triple values
This tables on the left column starts with 0, and goes 1 2 3 4 5 6 7 8 9 10 etc...
This is each cylinder event, from what I understand,
usually notice the first cylinder event is 1.25 at the top, very little fuel going in on the first crank trigger
Change this to like 3 , 4 or 6
then interpolate down slightly 5.5 5.2 4.8 4.5 4.2 etc... to test
Look in my tune file for example of my 5.3L Starts very fast
https://forum.hptuners.com/showthrea...l=1#post686802