Help with Monoprice Select v2

I've been printing for the last year or so with no issues then the other day I started getting warping problems and on certain prints (with the same exact settings as my other items) it was not printing. The printer would keep going like it was but nothing was coming out. Of course I assumed a jam so I'd clean it and try again and same thing. I even paused a print, raised it up, fed it through so I know there was no clog and resumed the print but still nothing would come out. If i have a raft or brim it will print that and like the first layer then thats where it messes up. I've been trying to figure this out but Im ready to toss it out the window its driving me crazy. I even test printed something older and it printed fine. On the thing it wont print i'll try different locations and angles, same results. Its like theres a gremlin in there. Anyone have any ideas? Like i said i releveled it, its PLA (not new since this issue)

Sounds like your slicer changed a critical setting if older prints are working. Maybe compare the files to see if a temperature or feed setting is significantly different from what you expected. ...or the "something older" is a red herring.

Thanks for the reply, yeah I got it dialed in a little better with a re-leveling after replacing the PTFE tube, turns out it had been awhile. PTFE tube looked fine so i'm thinking the leveling helped a bit. I'm still getting a bit of stringing and every so often my first layer likes to curl up in some spots, but I'm trying to find some happy ground. I may grab a fresh nozzle (and some more spare tube) but I think i'm gonna upgrade the cooling fan shroud since this one blows kinda directly on the hotend/nozzle on one side. I'm gonna try a shroud that blows all around and more down toward the material. I also lowered the temps from 210 to 200 for pla and it maybe that helped, gonna play around with more temps.

I have a closed system but I now have the option to play with various materials. One thing that I give attention to is to have PLA nozzles and ABS/PETG nozzles. Only because I know what carbon residue can do from burned -anything-. The more it "carbonizes", the more stuck it gets. It is a molecular bond thing highly dependent on materials, of course, but I do know that PLA will turn to carbon over time with elevated temperatures. My machines run ABS at 260C and first layer PETG at 265C. If that nozzle has any PLA remaining, it will soon become a block or a dam within the tiny space of the nozzle aperture. Dust particles can do this too but normally they are just swallowed up in -melt- and become black blobs, also problematic over time. Only recently did I learn about "cold pulls". If there is any hope of removing stubborn particles from inside your nozzles, that would be it. Unfortunately, my nozzles aren't quite as simple to maintain as most.

I think that melt and extrude issues are the hardest things to get over when you need to dial in a material or a special print. I prefer the closed systems for that alone. You know it -should- work. Good recipes, which our profiles are, are not simple to come by.

Yeah I cleaned out the nozzle when I was in there as well, but I'd like some fresh one just because its good to have. I've only been using PLA as of now but I have a roll of PETG and ABS i plan to try and use at some point. The PETG very soon, but i'm gonna build an enclosure to help trap the heat in for when I'm ready to try ABS. Stepping stones. Petg should serve fine for most my applications (plastic car pieces that can survive without warping trapped in a car in the sun on a hot day), but I'd like to learn ABS in case I need it in any extreme cases. I'm using the Maker Select v2 right now, but if I get this dialed in and operating relatively smoothly I may grab a Prusa i3 Mk3 as an upgrade

Interesting. Some will tell you that PETG is the new ABS. Having a little experience with it, I can see why.
But warp tendencies with PETG are somewhat all over the map is seems. I have clear that doesn't warp! I know that's a bold statement, but then I try the Amazon black PETG and it is as bad if not worse than my ABS. I can only attribute this to colorizing pellets being more like ABS rather than the nature of clear PETG. But this is a lot of speculation.

I don't have a heated bed so managing ABS can be tricky but I've learned a few tricks over time. If I keep the room at 70F or better, it seems to do okay. I will also pre-warm my aluminum build plate on the stove. Nothing drastic, just warmed up enough to take off the first layer thermal shock. My plate's magnets don't like high temps!

Oh no, Amazon Basic is the exact PETG i have! lol, its translucent though not solid color. What Petg are you using that you've had success with? I've only used Amazon and Maker Greek stuff at this point. I was gonna try to branch out to Hatchbox, Inland, and some others on amazon. Maker Greek has a huge problem with shipping orders. I got my first order pretty quick but my second never came, no answered emails so I had my credit card drop the charge and im done with that guy. I have a heated plate, but I heard its still good to get an enclosure to help trap the heat and coat the plate with ABS/acetone mixture

NovaMaker, also from amazon: https://www.amazon.com/gp/product/B0746DXJ8F
The batch I got works very well albeit stringy is all PETG is. But the prints have been fantastic!