MMM and eagletree rpm sensor problem.

[Just go Play]

In your case with the occasional spikes you can limit them (in amplitude not frequency) by setting the max range for that input. So if you know that the highest RPM you would ever see was 35000 set that as the max range so that you will not have off the scale readings messing with your graphs.

This does not fix anything but it will make it less annoying to look at.

Oddly enough I only tend to see those spikes when I power the system up or down.

[MTBikerTim]

I get those spike on my mini-t (Quark 33amp Pro-car) when I power it up as well but the MMM is a different beast. I forgot to mention as well that I do have both wires connected. I haven't yet tested the rpm meter on anything else. I don't really want to limit the graph as I want to see how hard it revs doing back flips and things.