The extruder is behaving abnormally: when starting a print, it continuously spins in the opposite direction of filament feed. In the video, you can see that when I command extrusion, it starts by pulling the filament as expected, but shortly after, it keeps spinning and pushes the filament out.
I’ve already cleaned and inspected the extruder — there’s nothing visibly damaged or clogged. Here’s the video showing the behavior.
In new tests, I marked the motor with a pen to better see the rotation direction. When I command it to extrude, it spins quickly as if waiting for the filament, but once I insert the filament, it spins rapidly in the opposite direction, pushing the filament out. Could someone help me with a solution?
What happens when you push the filament right down into the start of the nozzle and the then hit extrude?
I started without the filament because before recognizing the filament it turns quickly to push and after recognizing the filament it turns quickly to remove the filament and this makes it impossible to print any part.
are you using CFS or external side spool ?
if you look at the left side of the extruder with the cover/protector off, you should be able to see one of the gears working, I couldn’t tell from the video which direction it was going… but if you look at the left side of the extruder - gear that is visible with the cover off, it will be clearer whats happening.
first thing to check is, what filament type - settings are you using… vs comapre to the actual spool being used…
A bit more info will make it easier to diagnose whats going on
Hey sure, I’m now using the external spool, using PETG but the error is with all filaments. I’ve already checked everything, unclogged nozzle, gear without anything broken, but when I start printing or simply tell the filament to extrude, it spins quickly to extrude and as soon as it starts it stops and spins in reverse pulling the filament out without stopping and fast as in the video.
any system messages ? or does it just reject-spit out the filament without any reason
not had this before myself…
your video shows that the CFS is not connected/detected, did you disconnect half of it ? or not have one at all… I’m wondering if you’ve disconnected half the CFS and its still detecting the 4-1 merge - filament runout - blockage detector… (the 4 → 1 box you install on the back )
I know when it goes to cut the filament for switching (or retracting) you see it do a few turns forwards/backwards after the cut is executed… but I don’t get continuous retracting except when the machine still thinks its on CFS mode…
i,e when you have ptfe connection failure and thhe ptfe pops out you get meters of filament inside the enclosure because the ptfe has been ejected, I use the CFS retract feature to rewind the many metres of filament back to the spool…
Also, how long since you performed extruder motor stepper calibration (or never), if you’ve done that in the past, the instructions have changed…
Things I’ve tried. I rolled back a firmware version, did a full calibration, removed the CFS, and still the result is always the same. The motor spins fast, removing the filament from the extruder. I don’t know what else to do. I bought an extruder, motor, and board to replace, but it will still take a while to arrive.
full calibration, I assume you mean normal calibration through the system menu’s (like when you post firmware update), a stepper motor calibration is a different process, you load a macro from the creality wiki & execute code to re-tune the motor used by the extruder.
try that if you haven’t already before replacing any hardware
I followed your step-by-step instructions and everything went smoothly during the process. However, after restarting and testing, the error still persists. The video below shows the motor spinning rapidly in the direction that pushes the filament out. I added a mark on the pulley to help visualize the rotation direction more clearly.
Ok…
Assume you have tried completely removing the ptfe and just tried the filament directly into the extruder
Are all the cfs cables removed from the K2 ?
Probably need to upload the logs to see what commands it is executing…
And if nothing untoward in the logs, might be a creality support ticket required 
Yes, I already did this and put the filament directly in, Creality support asked me to wait and they haven’t contacted me yet, 
Can you upload your printer.cfg as well as klippy.log & moonraker.log
I restored the factory default and had it extrude using the filament in the cfs, it pulled from the cfs normally and when the extrusion started it started to rotate like in the video.
link with logs: k2plus log - Google Drive
printer & moonraker both look good, compared against mine, nothing looks out untoward in those 2, however…
Klipper shows lots of 485 serial connection errors and you are suffering from MCU connection timeouts…
One thing that stands out is your setup is using ei input shaping, I don’t know if that has any effect just an oddity, I thought “ei” was mainly used on bed slingers, I’m using mvz input shaping algorithms myself… and I don’t remember changing from defaults (remember being the optimal word) 
but then I’ve played around so much I can’t actually remember.
Start with… Completely disconnect all cables from the K2, unplug the power for 1 minute to let everything in ram be wiped.
Only connect the power cable… no other cables.
Turn on and rerun input shaping.
Try to extrude…
If this fails …
Then I suspect you have to go down this route:
It’s a bit involved, and frankly you shouldn’t have to do this, but to get a working system again this may be necessary.
Something to try at least, while waiting for support to get back to you…
Chris
I changed the motor and extruder and now the noise and uncontrolled rotation no longer occur, however the motor does not rotate and gives error CM2784
Hallo,
ich habe seit 2 Tagen das gleiche Problem!
Ich startete einen Druck mit Kalibrierung, zur Kalibrierung kam es dann nicht mehr, bereits dort drehte sich der Extruder in die falsche Richtung, das ich aber erst bemerkte als ich meinen Druck über die App kontrollieren wollte und sah das ich nichts sah. Der Druck wurde abgearbeitet ohne eine Extrusion.
Dann ging ich auf Fehlersuche: zuerst musste ich das Filament aus dem Extruder entfernen, danach hatte ich den gleichen Ablauf und Versuche wie schon bei “Rafatech”, alles nichts gebracht.
Hinzu kommt noch ein Fehler der mir aufgefallen ist: Befehl händig, das CFS soll laden und extrudieren.
CFS läd - Extruder läuft links rum, also falsch herum. Der Vorgang stoppt nach Ablauf einer zeit, als wäre der Ablauf richtig verlaufen und keine Fehlermeldung. Darauf habe ich versucht mit dem Befehl “Rückziehen” das Filament wieder zu entladen, ging nicht, Extruder lief wieder links rum (richtig) aber das CFS machte keine Bewegung und wickelte die Spule nicht auf.
Ich weiß nicht mehr weiter, außer den Extruder-Motor auszutauschen und zu hoffen.
Ich kann es nicht nachvollziehen.
14 Tage habe ich den K2 Plus jetzt, nix alles super und dann das!
Nachtrag: Extrudieren über das Fluidd-Dashboard ging zweimal richtig, beim dritten mal drehte sich plötzlich der Extruder wieder links herum (Rückzug) und das auch noch endlos.
Könnte es sein das der Filament Sensor defekt ist und falsche Signale sendet?
I’m waiting for my filament motor to arrive, change it and test it, I’ve been trying to solve this for so long that I’m not even hopeful that it will solve it.