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&nbsp;mm filament through a 0.4&nbsp;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&nbsp;mm Filament for Creality 3D. The same problem remained. 
I did the extruder test with 120&nbsp;mm marked on the filament and only about 60&nbsp;mm went through. 
By increasing the flow to 150&nbsp;% 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&nbsp;mm you should preheat the nozzle before the gcode G1 E100 F100 ; Extrude 100&nbsp;mm at 100&nbsp;mm a minute is issued.
Is there any point in removing the nozzle or the feed tube and issuing this 100&nbsp;mm/100&nbsp;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&nbsp;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?
OK, I have my Ender 3 back to printing nice looking objects. It turns out at some point since the original bad E-stepper I must have pushed the "load settings" menu item. I set my E steps to 98 from 93. and then did a "save settings". I have no idea why going from 93 to 98.03 increased my extrusion from 40mm to 100mm (trial and error, because the formula said I needed to go to 232.5!).
For those that don't know, the "save settings" stores the current settings in EEPROM. These setting override the factory configuration setting when you reboot. If while you are messing with setting and you lose track of things you can do a "load settings" to get your previous settings back to start again. The "initialize EEPROM" reloads the stored configuration settings including the settings that you saved. 
More intelligent explanation here: