New Firmware and V2 head causing over extrusion

So I picked up the latest V2 extruder for my Taz3. I did the install following the online “Ohai kit” instructions. I also installed the new firmware. I started a print and it was WAY over extruding. Almost 2 times the needed flow rate. It was so bad that it started building up filament on the bed so badly that it snapped the heater block clean off. Ruined the new head. Long story short, I just got the new head installed and don’t want to have the same issue. Why is the head way over extruding? Also, how can I adjust the flow rate. I turned the dial down during a print showing the “FR” percent decreasing. I assumed “FR” was flow rate and that lowering the percent would lower the amount of filament coming out. instead, it just slowed the movement of the head down and not the amount of filament. I’m sure this is a simple fix but I’m not sure what to do and I can’t risk snapping another head. These are stupid expensive. I need to get this fixed before I start printing. Any suggestions would be greatly appreciated.

I may have been wrong with my assumption of the extruder over extruding. I just started a print and sat and watched the first layer print. The first and 2nd printed beautifully but the 3rd layer on looked horrible. It looks like the Z axis is not raising enough for each layer which is just smashing the next layer on top of the last. I had to stop the print on layer 5 because the build up was getting pretty severe and I was afraid I was going to snap another head. Either the Z axis is off or I am over extruding OR a combination of both. Hopefully somebody has had a similar problem and can help me out.

Whenever you put new firmware in you need to calibrate the Esteps. It’s best to start with the old numbers but if you did not copy them down you need to start from scratch.

Here is a photo of mine to get you started but you need to calibrate the Esteps to your unit. Basically you tell it to extrude 100mm and see if it uses exactly 100mm of filament (going in not out). and you can then adjust the steps until it’s accurate and save it. Somewhere on this site there are step by step instructions if you can’t figure this out.

Now, since yours is extruding so much to break things, then start by making the Estep much smaller than it currently is.

Hope this helps.

I was composing my reply as you posted. You can also use my image to see the Zsteps and see if your’s is close. Also in your slicer what layer size did you set? If you set it too small by accident it may not work.

Also did you use the instructions and firmware for the TAZ 5? That is the one for the Hex hotend.

I use .3mm layer height. I am printing large objects in the 20-30 hour range. You can see my site at to get an idea on what I’m making. My other 11 machines are all makerbot clones or actual makerbots. This TAZ is an entirely different beast. I speak fluent Makerbot but every time I work on the TAZ; it’s like trying to read greek. It’s just an entirely different way of thinking. In regards to the firmware; I used the TAZ5 firmware through the new Cura software. I did it while on the phone with one of the Lulzbot guys. Everything seemed to be working correctly.

I just checked my step setting and they are identical to yours except my Esteps are 850 and your’s is 886.

So I did the extrusion test of measuring 100mm of filament and then having the machine extrude 100mm using the dial. It extruded 98mm, 98.5mm, and 99mm on each test. So the machine is actually under extruding. That tells me that the Z layer height is all messed up. How do I fix that?

That’s actually pretty close but you can change it right on the machine, you see the little > in my photo, just put that onto the estep using the dial then then press the dial in, it will switch to a screen showing your Estep and you can change it with the dial. Higher numbers = more extrusion.

Once done back out of the menu until you see “Store memory” and put the > on that and press the dial, it will then save that setting.

You can try the setting without saving but if your machine reboots it will be gone. Also you can change these settings on the fly while printing. Kinda neat that way.

You can also test your Z axis the same basic way as the extrusion, mark a spot where you can see how high the Z axis is then tell it to move up 100mm and measure.

If you have a .35mm nozzle you really should not have a layer height more than .25mm.

I hope this helps.