@good1228 said in Dual Z problem with Version 1.21:

Im having an issue where my dual z motors move at different speeds after an upgrade to 1.21.
its on a wanhao di3 printer.
It homes x and y correctly, and was working until i upgraded.

I don't see any M584 command in your config.g, so I presume that you have the Z motors connected to the Za and Zb motor connectors. Is that the case? If so then your Z axis is probably binding, perhaps because the two motors have got out of sync, or because the motor current is too low.

also another issue i have is that when a print would complete (back when it worked) the exruder would go in reverse for about 10 mins and i had to hard power it down.. not sure what thats about either. i do i have a duet wifi for my delta as well and no issues.

See @deckingman's response. You need to add either M83 or G92 E0 before the G1 E-nnn command in your slicer end gcode (or in stop.g if that is where you have it).