the car is a holden monaro 2002. previous to installation there was alternator whine. This is with nothing connected. no speakers no amps etc.

With installation of the car pc using a liliput screen and m2-atx. I have screen flicker which modulates during engine rpm and the whine is much loader.

The screen seems to ground itself through the vga cable to the computer when I disconnect the screen ground from the ground on the cars wiring harness.

The amp and computer are both connected to the same clean ground point.

Now im sure its bad grounding but ive tried as much as i have thought. tried grounding the screen to body rather than harness still flicker.

any ideas please?