Most likely stepper motor voltage needs to be adjusted.
There are numerous posts on this issue, please use the search function.
Also, please gain some experience with PLA before attempting ABS.
I had an issue with the extruder motor when i first built my K8200. 3 things need checking. 1) the nut on the Hob bolt can be too tight, 2) the motor and the extruder gear may be too close, move them apart a tiny bit, 3) the thermistor may not be in the hole, or you may have some plastic leaking from the extruder which is insulating the thermistor (mine started smoking!!) I hope this helps someone.