fuel gauge help

[69heavychevy]

So after years of having a non-functional fuel gauge I finally decided to do something about it. I knew my sender was shot but when I disconected the brown wire it stayed at the 3 o'clock position. Then I completely removed the wire to check for any shorts, it was good. I then grounded the fuel gauge terminal at the fuse box and it shot back to empty. Also when my tank was near empty the gauge would float all around. Any ideas on what the problem could be??

[bosco200]

When its near empty how much does it float around.....does it do it when your going around turn? cuz thats normal.

[Sammy]

I just tinkered with mine the other day. I'm convinced mine is related to the sending unit or the little resistor on the back of the gage itself. Addtionally I took a new out of the box (sending float assy) and checked the ohms to compare it to mine. Stamped on the side says 90 OHMS. The new one only reads 80 my old one reads 85 ohms at full with the float to the full swing. When my tank is full it is only showing about half full. The noise of the sloshing of the float could be normal or you could have some extra stuff inside.

[69heavychevy]

it will float during turns and even when sitting at a stop light...what has me stumped is the fact that it stays at the 3 o'clock position even with the sender wire unhooked. thats usually mean theres a short somewhere on the wire but thats not the case.

[dmack91]

Mine did the same - 3 o'clock unless grounded, then went to empty.

Bad sending unit. $30 part and all is good now (thanks to Vettevet's help).

Here are the responses I got when I asked the same question.

http://67-72chevytrucks.com/vboard/s...l+sending+unit

[69heavychevy]

thanks for the reply dmack, i wish i had come across your thread when i was searching different post. lots of good info there. im going to check for the fuel tank ground tomorrow.

[brad_man_72]

my fuel gauge didn't work ever since I installed m new fuel cell (2 years) as I was getting ready to cut a big hole in my tank and modify a factory sender I noticed the new aftermarket sender had a loose wire inside the tank. Gotta love paying top dollar for professional work.

[northerngmc]

Here is a guide I used when I was working on the sending unit in my 69 GMC.

http://www.6066gmcguy.org/Electrical-02.htm

[oldgold70c10]

That is kind of normal for it to go towards 3 o'clock position with sender wire unhooked. If the sender wire shorted out (shorted to ground), it would read empty. Either your sender is bad, or the sender wire has a bad spot somewhere.