Did you hook it up according to this datasheet:
http://www2.usfirst.org/2006comp/oth..._Operation.pdf
If you did, it's possible that you just have a faulty gear tooth sensor.
EDIT: Make sure that you didnt accidentally get some solder between the wires on the other side of the board, that's happened to me. Also, if you are bolting it to your frame, make sure you put electrical tape on the side that's being bolted so you don't short out the leads on the frame.