I finally saw what a bad ground wire does to an engine over 6 months

My neighbor's Taurus ran fine for years until he started getting random misfires about 6 months ago. The battery terminals looked clean on top but when he finally pulled the negative cable, the inside was green and crusty. That bad ground caused his alternator to work overtime and killed a $120 battery in just 4 months. He also lost his radio presets and dash lights flickered. I helped him wire wheel the terminal and replace the cable end for $8 total, and it runs smooth again. Has anyone else chased a misfire for months only to find it was just a ground issue?

2 comments

2 Comments

jana_miller316d ago

The "inside was green and crusty" part is actually pretty common and usually not a bad ground issue itself. A bad ground is when the cable connection is loose, corroded, or broken, not just dirty terminals. That green crust is actually battery terminal corrosion from acid fumes. Cleaning it fixed the connection, but the real problem was probably a bad battery cable end that wasn't making solid contact. I've seen dirty terminals cause weird electrical gremlins, but a true bad ground from the engine block to the chassis or battery to body is what really kills alternators and batteries over time. You might want to check his engine ground strap too, those can rot out internally and cause the same symptoms.

alice_wilson735d agoMost Upvoted

You ever read that old forum post where a guy spent months chasing electrical problems, replaced three alternators, and it turned out to be a ground strap that looked fine on the outside but was totally rotted through inside the rubber? I swear, those engine ground straps are the silent killers. They can look perfect until you actually flex them and see the corrosion inside. Same with the battery negative cable going to the body, I've had those where the terminal at the battery looked clean but the connection where it bolted to the frame was all rusted out underneath. Makes you wonder how many perfectly good parts get swapped for no reason.