I got a 3D printer kit that I bought to better understand it when

I got a 3D printer kit that I bought to better understand it when building my own customized one. I put it together but the z-axis doesn’t go all the way up and down. I made a video and wonder if someone could check it and and see what the issue is.
https://docs.google.com/file/d/0BxWkyuHWaCs5M25maU1yVVRCbTA/edit?usp=docslist_api

from a cursory glance at the video, it looks like the left Z motor isn’t spinning - double check connections to the motor? on the Z axis both motors should be turning at the same time.

They are on a single driver. I rechecked the connections numerous times. I took off the top bracket and let it hang and tested it. After that it started to work fine.

This kit had a lot of troubleshooting. Now I’m trying to figure out why the first few layers don’t print properly: https://docs.google.com/file/d/0BxWkyuHWaCs5RDZnZEtHbmw0ZUk/edit?usp=docslist_api.

The first couple layers are stringy. The layer that encircles the print doesn’t even make on the bed. It seems like its not extruding fast enough? I ran out of the PLA that came with it and I haven’t had enough time to get the ABS to print properly.

The layer that encircles the print it starts extruding when it’s almost done and it doesn’t stick at all really even with the hairspray. All layers except for the first few print fine. How would you tweak the retraction?

I do have a heated bed. I tried the first ABS print last night with the same object. I saw that it started warping then realized the heat wasn’t set properly.