Finally, after 2 weeks building it (this is my first 3D printer), I can print ! I had to solve few problems but now it kind of works. But I still have a strange trouble and no clue on how to solve it.
When starting a print, the printer auto level then starts the first layer. On the center position, the Z height is correct but on the front side on the Y axis (towards the screen), nozzle is too high so hardly sticks to the bed while on the rear side of the Y axis, nozzle is too low so I nearly have no filament on the bed.
This trouble is only on the Y axis. The X axis keeps the same Z nozzle height.
As the printer auto level, I don't understand why this happens. I see no way to solve this problem. As there are 2 step motors for the Z, I tried to manually lower the front one to compensate before power on but it changes nothing. It's like the auto level is making a mistake.
I have the dual extruder Proforge 2S and the upgraded heated bed and flex plate.