I've had my Ender 3 Pro for a few months, and it's been working great. Then, after a failed print (the STL had extra seams, causing the print to get mangled), I've started having issues that I have attributed to under-extrusion.

As evidenced by the below image, some lines in each layer are missing. The gaps align throughout the print, but not between prints (the two squares are identical G-code). This happens in every layer, with a different pattern in each. It also causes some perimeters to not adhere to the previous layer at all.

The extra strands in the right print are present because I ripped off the infill layer that printed on top before I aborted the print.

I first assumed I needed to calibrate my extruder. It turns out I did (93 had to be changed to 150 steps/mm). However, that did not fix the issue.

Some things I've tried:

  • Calibrate the extruder
  • Check nozzle size and filament size in Slic3r
  • Level the bed (I had to place a post-it note under the centre of the flexible magnetic build surface to make up for a warped bed)
  • Clean my nozzle and hotend (I fully dismantled the hotend)
  • Replace my nozzle
  • Increase printing temperature

Is there anything else I might try to get this fixed?

Evidence Image

Specs for Reference:

  • Ender 3 Pro
  • 0.4 mm Brass Nozzle
  • 205 °C Hotend
  • 60 °C Bed
  • Slic3r
  • 150 Steps/mm for Extruder

If you need any more information, just comment and I'll do my best to supply it.

Please note that I am not open to suggestions to replace my printer. I'd rather fix the one I have.


2 Answers 2


It turns out the extruder was slipping, but not due to a nozzle or Bowden tube pressure issue. The extruder arm (?) that holds the passive wheel (as opposed to the drive gear) was cracked, so the pressure between the wheel and the gear was weak. A bit of glue fixed it.

These printers should ship with metal extruders, I think.


The arm broke again, and this time I have a picture to illustrate the issue. I didn't make the printer do anything strenuous; I just printed a few small parts, causing it to break. enter image description here

  • 2
    $\begingroup$ This is a very common issue, hence the need for more steps for the extruder, thanks for getting back to post an answer! It would be a bonus of you could add an image of the cracked lever to the answer! You can even accept the answer after 48 hours. Please consider upvoting the answer from @R.. as this leads to the solution you posted! $\endgroup$
    – 0scar
    Commented Aug 13, 2021 at 8:17
  • $\begingroup$ I fixed the lever before I had a chance to photograph it, unfortunately. $\endgroup$
    – tjcaul
    Commented Aug 14, 2021 at 18:04
  • 1
    $\begingroup$ The part is called the "Extruder Feeder Drive" if anyone is looking to get a replacement $\endgroup$ Commented Dec 2, 2022 at 13:24

This is a big red flag and severely wrong:

93 had to be changed to 150 steps/mm

It can be reasonable to tune steps per mm by a few percent, but needing an increase of more than 50% versus the standard value for the same physical gearing indicates either you did something wrong in computing the needed value, or some other serious root problem with the printer.

You should start by fixing that (putting it back at 93) then try to figure out why it seemed to need change.

Likely your extruder isn't gripping the filament. Trying to overextrude that severely likely grinds it so bad the hob fills up with shavings then doesn't grip at all.

  • 3
    $\begingroup$ This answer clearly explains that a sudden increase in E-steps is a flag that something has completely gone wrong. This led the OP to find that the extruder indeed had a fundamental problem. It is very good to have this answer together with the answer of the findings of the OP! Thanks! $\endgroup$
    – 0scar
    Commented Aug 13, 2021 at 22:09
  • $\begingroup$ I saw some sites suggesting that drastic changes in steps/mm for the factory extruders could be necessary. Clearly that’s not true. $\endgroup$
    – tjcaul
    Commented Aug 14, 2021 at 18:05
  • 1
    $\begingroup$ @Fluzzlesnuff A manufacturer provides a working 3D printer, a large/drastic change shouldn't be required. If it doesn't work out of the box, you should contact the manufacturer. However, very small changes are possible, e.g. when filament is softer, the teeth dig in more decreasing the effective extruder gear diameter, but, this can be altered with the flow modifier. $\endgroup$
    – 0scar
    Commented Aug 14, 2021 at 21:46

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