Autotuning PID

M500 is a separate command sent after your PID numbers

so you would do something like this:
     M301 P19.56 I0.71 D134.26  >enter
     M500 >enter

Thank you heartless for the reply. That helps a lot.

elmoret, the heater has a resistance of 6 ohms.

I'd love to upgrade, but I have no idea what I'm looking at. Here's a picture, can you point me in the right direction?

Ahhhhh, okay, that part does slide faily easy and it is 6mm.

It slides easily without loosening any type of screw?  If it is not tight, you could be losing some heat transfer...

There's not a screw to be loosened. When I say "fairly easy" i mean applying about a pound of force with a blunt tool. Do you think that could be part of my problem? Seems like a design problem to me.

Yeah, the old way was to use a setscrew, but that wasn't all that much better. The correct way is a clamping style fixture, like E3Dv6's:

Are they really only using one 24w heater for that huge block? Yikes.

You should be fine drilling and tapping a set screw and using a 40w heater. You could also try wrapping the heater block in high temperature insulation.

I didn't notice that...one heater for both nozzles?
A - not enough power...
B - how do you print ABS / PLA combinations which would require 2 separate heat settings?

I would also switch to a cartridge type heater for the fact those heaters you are  using are nothing but high wattage low ohm resistors that reach near red hot temps and burn out easily and are more of a fire hazard.

Those types of heaters are very old out dated tech from before the 12 and 24 volt cartridges where introduced.

Wow...and last I knew, the TPU / ABS combination they used in their demo video would require around 180/230C respectively...I could be wrong as I never ran TPU, but the EcoFlex I run needs about 180 as well.