I have been having MAJOR ground offset issues with my LC-1. My Hptuners serial EIO just went south so I am upgrading to the MPVI EIO. I removed all engine wiring over winter for the 408 install and I wonder if I didnt replace the Main/PCM ground in the wrong place.

What ground cable does the diagnostic port(EIO uses this I believe) use for its ground? Also, could someone who has not moved this ground please look at where it is attached to the car and let me know?!

Thanks all.

 

Anyone?