I'm guessing that you accidentally reversed the internal connection to either coil. In other words, you got black and white, or red and green reversed on the coils. To do a simple test, simply reverse either pair. That is, use black for hot, red for ground, and short white and green together. If that solves the problem, then do this test: (or do this test to start with)
Connect a meter to black and white using the red meter lead to black and the black meter lead to white. Make sure you get around half your total ohms measurement. Now switch to the lowest DC volts setting. Bring a screwdriver up against the stud poles gently. (Don't "whack" the pole pieces.) Then yank the screwdriver away. You should get a positive voltage spike as you approach the poles, and a negative spike as you pull away. If its opposite, thats the coil thats backwards.
If its ok, then do the same with the red/green wires, connecting the red meter lead to the red wire and the black meter lead to the green wire. Now do the screwdriver thing to the screw coil. You should still get positive as you approach and negative as you pull away. If not,
that's the coil thats backwards.
Edit: Here's my webpage that goes into a little more detail. It was intended for a different thing, but it works just the same.
pickup-id.html