Holler Sniper EFI & Hyperspark Starting Issues- Worth the read.

Did you replace the O2 sensor? Maybe I missed that?

Not sure why it would go bad, but since it is a self learning system bad input would mess things up. So an O2 sensor that is reading lean maybe could result in the injectors going full open? Maybe the bad ground caused the system to go lean, pushing the fuel to max and resulting in ruining the O2 sensor due to either a backfire or flooding?

My other guess is that the loose ground fried the ECM.

Maybe try and replace the O2 sensor, reset the ECM and try it again. If it runs rough, I would shut it down right away and look at replacing the ECM.

But just guesses on my part, I don't have any experience with the Sniper systems or anything.