Calibrating the ZREFs for the E motor fixed this problem for me.
http://3dprinterwiki.info/wiki/wanhao-duplicator-i3/duplicator-i3-calibration/setting-the-stepper-current-on-the-melzi-board/
Calibrating the ZREFs for the E motor fixed this problem for me.
http://3dprinterwiki.info/wiki/wanhao-duplicator-i3/duplicator-i3-calibration/setting-the-stepper-current-on-the-melzi-board/