Hi, my fuel gauge is not functioning. It doesn't matter that much, but it is kinda annoying at times. So I was wondering if I can get it fixed. But first I need to know what is most likely the cause of it. The needle is always at the 'full' mark. Not mather how much gas is in it, ignition on/off. I haven't seen the needle move since I own this car (about 3 months now). What could be the cause of this (the needle always pointing at 'full')? Gauge just broke? Of maybe the sending unit? If it is the sending unit, anyone know what kind of sending unit it is? It's a 1975 car. And I mean how much ohms is full and how much ohms is empty. Maybe I can check if my send unit is still okay.
When it loses ground it will peg all the way past full and not move, I have seen a bent float also do that from someone shoving a garden hose down the tank. Mine was a ground issue with the ground wire at the sending unit. Steve
Ground was one of the first things that crossed my mind too. But if I understand correctly, the sending unit has a ground wire also? On the wiring diagrams that I have I can only see one tan colored wire. Coming from the sending unit, going into the trunk and runs with the rest of the tail light wiring to the front of the car (this tan wire goes to the fuel gauge). EDIT: I checked the wiring diagram and yes, the sending unit has a ground wire too (sorry didn't know that, but makes sense now!) So this is where I need to looks first? Crawl under the car and inspect the wires coming from the sending unit? I have never really inspected it. When I look under the car I can see that tan wire. I will look for a black one! The gauge itself has a ground wire too. But I will check the sending unit first. Thanks guys!
Well, I finally had time to check some stuff out today. At first I couldn't even find a black ground wire at the back. But I found on the other side of the gas tank (towards the front of the car). I checked the wire, even loosend it and ran a new wire from the negative pole on the battery and connected it to this ground wire (if that ain't good ground, I don't know what is :laugh. But it didn't change a thing. I also checked how much resistance the tan wire has (coming from the sending unit), and that was 38-39 Ohms. Does anyone know what kind of sending units GM used back in the 70's? Mine is a 1975 (Buick). I'd like to know how many Ohms means 'full' and how many means 'empty'.
