I have had the monoprice Maker select 3D printer V2 Model #13860 for a while now. Not thrilled with it but i've gotten it to work for me generally.
Recently i had to replace my ABS roll. Purchased exactly what i had just been using and the darn thing just won't print right for me anymore.
I tried getting a Creality Ender 3 Glass Bed Upgraded to help with the metal heated bed warping issues and that seems to have helped but didn't solve the problem.
I am getting a really inconsistent output from the extruder.
If the filament is taught (needs to rotate the filament roll) makes it much worse. If i pull the slack for it, that helps for a little while and then occasionally i'll get the inconsistent beading again.
I've messed with ABS for hours and hours. I've messed with PLA for a few hours now too. It gets better if i apply some pressure on the filament to feed it into the extruder body
I've taken apart the extruder / stepper body numerous times to try and figure it out.
Honestly about to just get a new printer unless someone can help me.
My guess is that there isn't enough pressure being applied by the spring to push the filament onto the feeder gear. This unit doesn't have an adjustable tension ability, just a spring.