Thanks
Poor (or absence of) ground can cause damage to some electronic circuits. Electronic ignition modules are one example. Other well known causes are using quick chargers (too high voltage) and doing arc welding on the car with the ECU in place.
I really think it was when I connected the gearbox ground while the battery was connected that did it. I've since installed a quick disconnect on the battery. I use a Deltran battery tender also, so nothing crazy.
