I am really stumped on this one.

I was having extruding issues the filament would extrude right up until the melt zone and then right as I get to the melt zone it just chews into the hobbed bolt

prusa i2 on ramps 1.4 with a mkiv-b jhead printing abs at 200-230c

oddly this happened right after I got a new roll of white abs filament from ebay.

I was able to print about 3 parts with it and everything was going nicely. then that's when the jamming happened.

I have been using same jhead a few months no issues. I pulled it all apart to find a clogged up wore out ptfe liner so I replaced that soaked the j head overnight in abs replaced the resistor with a 40w ceramic heater

im getting exact temp readings as far as I can tell but for some reason I just cant get this to extrude. I even tried pushing the filament through it so im not sure what my issue is bout to drive me crazy cause ive been wanting to do some printing for a week now

probably too hot for this feedstock. also some feedstock needs to be ran slower.

I took a break and thought about it. I found a old spring that was a spare uncoiled it and ran it around the inside of the j head and a clump came out now its working fine at least for now bout to try a test print and see><