Going crazy with new Duster and over voltage issue.

5. Checked and cleaned all grounds. Although i did notice there is no ground cable from block to firewall. There is a small ground off main battery ground that goes to front radiator support. I assume this is the ground for the chassis or is there supposed to be another from engine to firewall?
1st thing... Get a good heavy ground strap from block to body. Without it the current while starting has to find a path and it will go through any path it can find, through the transmission, the tailpipe, the gear shifter, etc.