Could be a couple of things. When I had mine I had a couple problems with it starting also. One could be the starter motor internal screws backed out and bound up the gears.
Another was the the motor kinda seized up (almost in the middle not even close to top dead center) so I took off the starter and left the one way bearing on and cranked it over with pliers to break it loose.
And one of the last problems I had with it not starting besides the glow plug or plug wire was the piston gets stuck top dead center, Traxxas includes instructions to fix that problem or you can get them from their website.
Also depending on how good of a battery is in your starting wand if it isnt charged fully, even if there is power going to starter motor, it might not be able to actually start it.
Hope this helps you.