Ground loops are real!Yes I have had to explain to some car guys (re: carburetor guys learning FI stuff) how critical clean wiring, clean routing, and the effects of grounded, shielded, and drain grounds are on low volt systems
Some of the aftermarket EFI systems have the ECM in the throttle body (dumb... my Edelbrock is under the dash like factory), I started having those guys run a ground wire from the throttle body to the engine ground, and not just use the system ground back to the battery. It's like magic![]()