TwEECer issues

Okay wtf? I hooked the twEECer back up (I didn't slide the PCM all the way back into the kick panel, just left it out where it was accessible), went to start the stang, and got a buzzing noise, and the tach was reading like 400 with the engine NOT running. I didn't even bother starting it. When I clicked read EEC, everything came up "0". What the hell happened?

Yep, all 3 harnesses were connected (I only had to unplug 1 to get the PCM out actually). I pulled the tweecer off, I noticed some white crap on the J3 board, so I cleaned that off. Still didn't work. I pulled the tweecer off, started the car and it ran like it did before. So I just cleaned the board again, and am gonna see if it works. Question, when I'm trying to read the EEC, does the battery need to be hooked up? Does the ignition have to be on?