Just bought a '92 plymouth Acclaim with 37000 miles. It's in great shape but I'm not sure if the fuel guage is working. Only drove it home, less than 10 miles. Is the guage mechanical or electrical? The needle position doesn't change whether the ignition is on or not. If I step on the brakes hard, it seems like the needle moves a little. The needle is currently positioned past full position. Please advise how to check this.

There's a float inside the tank that the fuel gauge works off of. If you step on the brakes or accelerate hard it causes the gas inside the tank to slosh around and you can see the fuel gauge move when you do this. If you know the vehicle has gas in it, the best way to check if the gauge is bad is to drive around enough to where you should have burnt a noticeable amount of gas. If the gauge doesn't move, then there's something wrong with it.


Since the gauge moved when you braked hard, I would assume it's working properly because it picked up on the level change inside the tank where the float's at.