Problems with MeCreator2

[povlhp]

My MeCreator 2 is sometimes giving me lines with too little filament. It is new, had it for a few days only. New to 3D printing.
Did a test, warmed the head to 220C, and used Repetier to tell the printer to feed 100mm filament, it was feeding only 83mm.
Tried a tower where I went from 100 to 125% filament flow, and it started clicking probably around 110% (so still when it was pushing 10% too little).

See tower and a #3dprinty boat. Seems like the first layers with holes on the boat is the same level as the first issues on the tower, and the tower keeps having underextrusion problems (?). Some person suggested it is Z-axis issues, so lubricated with PTFE bicycle spray grease.

Other person suggested it is extrusion, and that E calibration will help the most. As I could find on the Internet, it seems like I need to change in formware, recompile and upload. No problem. But if I hear clicking like every 2 seconds, I likely can not feed much faster. And increasing in software did not help as you can see. Only seemed to give more issues, less extrusion. Any ideas on what I can do to help fix the issues

The 3Dprinty boat was supposed to use 4.9 meters of filament, which should weight in at around 3g/meter (assuming data from Internet on 330 meters/kg holds). So around 15g, But it comes out at 9.6g. So I clearly have under extrusion issues. Maybe the nozzle is 0.3 and not .4 ? How can I tell ? Or maybe something clogged ?

Sometimes I can print an almost perfect tower. The tower is just 1 layer wide printed as a spiral.

[povlhp]

Just one more info. Looked in the source code.
Configuration_adv.h

And I find
#define STEPS_MM_E 836

I find it interesting that I get very very close to 83mm movement when feeding 100mm from Repetier. Is it random, should this just be 1000 ? But then I still have the other issues withmore extrusion not seeing to have any positive effect.