Bouncing fuel gauge 73 240z

[Craig24]

 

Since I got the car the fuel gauge never worked. I had the tank restored by “Gas Tank RENU” I had the Z clinic shop in Austin install the tank with a new a sender unit.

The fuel gauge still didn’t work. I had the radio/dash panel out which gave me access to the gauge. I grounded the yellow wire and the needle moved, I stopped at ¾ full (never pegging gauge). I read you can damage the gauge. I tested the wires with my meter. With the ignition on I got just under 11 volts at the gauge connection.

I removed the gauge and cleaned the outside contacts. I installed the fuel gauge and it worked kind of. When I turn on the ignition the gauge floats constantly. First to near full, then hangs around half full momentarily, then near empty, then back up to near full. It constantly floats the range.  Any Ideas - Thanks

[SteveJ]

We had a thread not too long ago about the 73 fuel gauge. Read through this for some ideas and watch the video of the bench test that is linked in the thread.