brushless rpm sensor promplems

[zviper]

i just picked up a eagle tree 150A with a few temp sensors and the brushless rpm sensor everything reads fine except the rpm its show 5750rpm when not moving. i set the brushless rpm setting on the pc to 4 pole. i tried other pole options but still nothing close to 0. i did try without the data logger, esc and batt lead disconnected and i got it to read zero. im stumped and now sad can anyone help me please?