sounds like u shorted something out or maybe the ECU went crazy...
do try this....my 280zx and caddy did similar things with the clicking and going bizerk.
unplug the battery cables and cleanr them really good. use a file to scrap off some on the outside. i did this on both my cars and it worked fine after. the cables sometimes will create a film and it will restrict current flow from the battery. just ruff up the terminals on the battery and the connections. its free and cant hurt..