C2 Fuel Gauge

[Mark H.]

This one has me stumped. About 2 years ago I put in a new (Made in the USA) sending unit - and it worked great until about a month ago. When the tank is full, the gauge reads full. It never goes below 3/4 full. With the tan wire disconnected, it goes to 1/2. With the tan wire grounded, the gauge pegs past full. These symptoms do not match anything in my shop manual. Any ideas?

[Richard S.]

Re: C2 Fuel Gauge

Mark,
Some of the fuel sending units, about 2 years ago, were testing bad right out of the box....see the archives as I know there are at least a couple of threads on this subject. Good luck.

[Dick W.]

Re: C2 Fuel Gauge

It sounds like that the guage it's self has developed a problem. When you disconnect the wire at the sending unit it should read empty

[Dixon Green]

[Gerard F.]

Re: C2 Fuel Gauge

Mark,

An easy test of the sender unit is as follows:

1. Disconnect the 3 leads from the sender unit and connect an ohmmeter between the two ungrounded studs.

2. Move the float in the tank up for full, you should read around 90 ohms.
move the float down for empty, you should read around 0 ohms.

If the ohms stay steady, or go inthe opposite direction, you've got a problem with the sender.

I had the same symthoms as you describe on my 67, and I found that one of the leads to the sender had broken off inside the tank.

If the sender tests out as above, then you have a problem with the gage or the electrical feeding the sender. Try cleaning the sender terminals and tightening the terminal nuts,and reconnecting first, before you try anything else.

There is a comprehensive thread on this subject in the archives (May, 2002.

Hope this helps.

Jerry Fuccillo
#42179

[Mark H.]

Re: C2 Fuel Gauge

I will remove the tan and B/P wires at the sender and jump them together and see what happens, and report back. I hate to think the new sender I put in a couple of years ago is shot.