I have had my 3D printer for about 6 months and I am having trouble with the stepper motor (Nema 17 78 oz/in torque) pushing filament through the hot end. This has been a problem for a while now, but did not occur in the first few months of printing. The motor will push filament through until it gets to the hot end, then it stops pushing through, and twitches back and forth. any resistance applied to the shaft of the motor causes the same issue to two different motors.

Attempts at a solution:

  • Replaced the old stepper motor with the current Nema 17 one, still experiencing the same issue.
  • Thoroughly cleared the hot end of plastic, no jamming there.
  • Checked filament size, it is correct for the extruder.
  • Switched the stepper motors for the x-axis and extruder, works fine on the x-axis, not on the extruder.
  • Loosened the tension bolts for the filament, no changes.
  • This problem existed when I had a bad control board for the printer (caused other issues), but getting a new board did nothing to alleviate the problem with the extruder.

Could this be a simple issue of replacing the stepper motor cable? I’m out of ideas on what to try next, and I haven’t seen any fixes online for this issue.


Can you feed the filament through the hotend by hand?


Check or replace the cable. Very common to have cable issues. Also check out the stepper driver, swap it out and see.

Also check the hot end, PTFE tube etc.


Yes, it extrudes easily by hand.

I’ve checked the stepper drivers, and they all work. The hot end and PTFE tube also work fine.

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It seems down to a few things. Bad cable or bad board. Unless there is some other “pinch” point that is getting overlooked.

I had a filament feed issue and found the spool was working its way out on the holder then rubbing and causing resistance.

Does it still do it if you feed filament directly by hand?


Yes, unless I push the filament through with a lot of force. The motor is unable to push it through by itself, but with a lot of help it will extrude.

In addition to the good advice of @wirlybird has given, you could also adjust the current on the stepper driver. Depending on the drivers you have, this is usually adjusted by turning a physical trim pot on the driver itself with a small screw driver.


Right now it’s set to the default current, and I know that I have to turn it clockwise to increase it. Is there a threshold I should avoid?

Unless you have a multi-meter to check the Vref pin, the best metric is to monitor the heat. If the motor and/or driver is running very hot to the touch(warm is okay) then you want to turn it down.


What kind of printer is it? Are the two wheels that push the material clean? They can get gummed up and no longer grip the material. Are the two wheels under tension? When the material is pushed through the wheels, the material should have little dimples in it where the wheels grip tight.


I have had the same problem countless times and the main causes that I have found on my printer is that when the extruder gets too hot the heat creeps up the barrel and melts some of the plastic inside it, making it harder to get filament through. If I were you I would replace the barrel and maybe the nozzle. Also check the vref of the extruder motor and look up what it is supposed to be. I believe it’s somewhere around. 6 vref. I have noticed it helps to turn the extruder one up a bit to give it a little more current and power to turn the motor. I personally never liked the little peice of tubing in the barrel no matter what material it’s made of… I usually take that out


What if you try to push manually the filament through the extruder? Does the material come out? It shall come out very easily. I had also an issue with the extruder and in the end it was the toothed sprocket misaligned with the wire because the PLA extruder body was deformed. It was very small offset but was enough to prevent filament to be pushed out.


What hot end are you using? In my experience, poor feed is the result of the following:

- low temperature

- on e3D hot ends, check the PTFE tube. They should be replaced occasionally. If you’re not sure, replace it anyway.

- also on e3D, make sure the heater block, nozzle, and barrel are all tight

- drive gear alignment with the tension bearing

- drive gear clogged

- drive gear slipping

Run the stepper without it being installed. Check to make sure motion is smooth. Bad cable is a possibility. Also check the header on the board. If you replaced the motor with similar results, it’s not likely the motor. Could be current, low current will cause the motor to “clutch” and that produces an audible clicking sound.


Hi there

In your shoes I wolud check and/or rise the Vref value of the pololu of the referred extruder motor.

I rised up the Vref over the suggested value. The motor is a little bit warm during the whole (long) printing, but it works just fine.



Try lubricating your filament. Do one drop of canola oil on the end of your filament then feed it in. Also you can take a paper towel and a binder clip to make an oiler that lubes the filament before it enters your ptfe tubing. I find that especially with PLA, this really helps on both my direct drive and Bowden printers.

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I do this almost every time I reload the filament, it doesn’t seem to do much for ABS or PLA. Thanks for the help though.

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How would I go about changing this? I have tried to adjust the current, but it didn’t seem to do anything. I just need a bit more detail, this is my first printer I have owned.

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There’s rarely an issue with the stepper motors. I’ve had feeding trouble, also, and it’s always been a mechanical issue such as the tension spring had too much or too little tension.

One other factor you may not be thinking about is thermal issues. If the ambient temperature in your printing area is too cold, you will have trouble with feeding.

Can you respond with specific details about what you’re seeing? For instance, when you preheat the hotend, then extrude do you see the hob rotate and chew up the filament? Does the hob NOT move? I think if you can paint a clearer picture for us we could help more.

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The stepper motor does not run smoothly, it will rotate on its own when it is not installed, but it has a very jerky motion. It’s a new motor, and the old motor does the same thing when connected to that cable.

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