Anyone have any ideas as to why a new stewart warner wings tach spins around 360 degrees over and over? 12 volts 31model a ford. Tach wire goes to neg side of coil. Stock 4banger engine with FS centrifugal advance electronic dizzy. It worked ok when I first hooked it up after second or third time driving the car it's all over the place.
Sounds like the magnet inside is sticking. Don't really have a solution, but that's what it sounds like. Wait, it's electronic ... Not quite sure then. At least you get a bump, lol.
Maybe the clock spring came unhooked. Normally the spring provides resistance. The stronger the signal, the farther it twists against the spring. Without the spring it could just spin as an electric motor until the indicator needle hit something. This is an old Sun. Others should be similar.
Mine does the same thing. Search older threads..... You are not alone. There was talk of some kind of noise suppression wired inline may help. I just deal with it.
Finally found n fixed this issue. After sending the tach back and getting a new one it did the same thing. Now i know its not the tach. I replaced the orange braided spark plug wires with regular 8mm rubber lines and it the tach now works as normal. I guess theres little to no insulation from the braided wires?