First, don’t use CM3 with Grbl 1.1 — it can cause weird problems — if you wish to use the machine w/o homing reflash to Grbl 0.9: GRBL 1.1 and Carbide Motion 4
I’d suggest going back to CM4, resending the defaults: http://docs.carbide3d.com/support/carbideupdater/#carbide-motion-v4 and resolving the homing — we have a basic page on that here: http://docs.carbide3d.com/software-faq/home-switch-troubleshooting/
Check to make sure that the X-axis wiring is correct/consistent with the other wires.
Make sure that the machine isn’t getting hung up mechanically.
If none of the above addresses the problem check in with support@carbide3d.com and we’ll do our best to help you sort this out.