engine and drivetrain fuel gauge registers half full when tank is empty, and other

[Guest Anonymous]

It's in my '72, the tank will be empty but the gauge says half full, when the float is at the top (tank full) the gauge says the tank is full, anyone have this happen and know how to fix it? I also posted before about my tank and was wondering how to get rid of the expansion tank in the trunk, would it work to connect the return line (from engine to expansion tank) to the line from the filler neck to the tank? Right now I have one line from the rubber filler neck to the expansion tank and one from the engine to the expansion tank. If needed I also have an extra lane coming out of my tank on top. I can take a pic if it would help. Thanks for any help/advice.

[Guest Anonymous]

Same thing happened to mine. If you take the sender out of the tank, you'll notice that the float rides up and down 2 little ultra-thin wires. My wires came undone..they are soldered on I believe. So the float could only travel down halfway..then it would get stuck. Putting in more than half a tank would raise it up though.

anyways, my solution was to find another sender.

matt

[Guest Anonymous]

That wouldn't make much sense though, not sure really. My other idea was that maybe I have to calibrate it in some way, such as hooking the sender up with the float all the way up then turning the car one then puting the sender in the tank, not sure how this would work but I'll try something like that maybe.

[Guest Anonymous]

i am going to check the two strings and see if they are ok.I read a while ago from a dwight chew or someone of the sort that you can repair this with fishing line.its a good idea to clean the rust out of the tube too.its hard to believe that rust finds its way through that mesh filter.If you are really ambitious take your tank down too a radiator shop and have them re-coat the inside.I think that it costs about 75 bucks.

Next i am going to try the gauges and senders electrics.COuld it be a bad ground?(previous owner put an earl scheib paintjob on the car ad i have found tons of bad grounds because everything was painted over)i noticed that whn i turned my heater on, the temp gauge shot up to almost full throttle.Check the croundings for the gauge cluster as well.

Well hope i helped,Let me know what you find so that i can look for it wheni am working on mine.

David Furey

73 2002-broken timing chain tensioner

68 1600-02-broken exhaust hanger

you just cant win somedays

[Guest Anonymous]

The little wires that the float rides on inside the sender unit are a specific type of resistance wire. Somwhere I've seen a post or a FAQ that lists the resistance in ohms per inch of wire. You cannot replace it with monofilament fishing line, as the float moving up and down the wires changes the resistance, thus changing the gauge reading.

If you're careful, you can dismantle the sending unit and repair the wire if it's just come loose. If it's broken, you'll have to find some wire with the same resistance (or find another sender)

If your gauge jumps when you turn the heater on, it's most likely a bad ground at the gauges. Pull your gauge cluster and make a small Y-shaped wiring harness. Run each short leg of the Y under the nut that hold the temp gauge and the gas gauge in the gauge housing. Then run the long leg of the Y to a convenient ground on the car body behind the instruments. If you can't find one, carefully drill a small hole in the sheet metal and run your ground to that. That'll usually stop the flickering gauge problem. If not, check the ground from battery to body and to engine.

Good luck

Mike