# Ender 3 under extrusion

I have a new Ender 3, it was printing fine using the Ultimaker Cura 4.1 slicer. I printed about 1/2 a roll of blue 1.75 mm filament through a 0.4 mm nozzle. All my prints were Ender 3 mods (plus one cover for a device I had).

Then it stopped printing 1/2 way through printing a bracket for the Y-axis to allow for a damper. After several days of under extruded parts that I aborted I discovered that the extruder motor was stopping intermittently and that turned out to be a bind in the motor. I replaced the motor, but it continued to under extrude. I replaced the stock extruder feed with Anpro Upgrade, MK8 Extruder Aluminum Alloy Block Bowden Extruder 1.75 mm Filament for Creality 3D. The same problem remained. I did the extruder test with 120 mm marked on the filament and only about 60 mm went through. By increasing the flow to 150 % I can print usable parts, but that seems like a bandaid covering up the real problem. Of course, I have cleaned the hotend, changed the nozzle and the feed tube. I have assumed that during the feed test of 100 mm you should preheat the nozzle before the gcode G1 E100 F100 ; Extrude 100 mm at 100 mm a minute is issued. Is there any point in removing the nozzle or the feed tube and issuing this 100 mm/100 mm command?

I have ordered a new hot end, but I'm beginning to suspect the board itself is not feeding correctly. Help?

I removed the Bowden tube from the hot end and issued the 'G1 E100 F100` and it feeds exactly 40 mm. Do I possibly have a second bad motor? I currently have no way of modifying the code on the board. Is there a factory reset for the Ender 3?

• Thanks for posting the answer, you can accept it after 24 hours by checking the tick mark next to the answer. Great that you managed to solve the issue by yourself! – 0scar Jul 27 '19 at 23:12