Can a Bugeye fuel tank sender be restored?

[ncbugeye]

First let me ask a question...

A Bugeye sender is just a resistor, right? So the fuel gauge is just an ohm-meter, passing its current to the chassis through the wiring in the sender unit.

If I connect an actual ohm-meter between the single terminal and the case of the sender unit, I'd expect to see the needle move as I slide the float backwards and forwards. Since I see a dead short all the time, either my ohm-meter is bad, or the sender unit is dead.

Can they be rewired, or is it not worth it? Moss quotes $49.95 to replace it, which doesn't sound unreasonable but if possible I'd prefer to restore.

Opinions?

 

[regularman]

I doubt you have a dead short, have you checked all the wiring? If worst comes to worst, send me the sender and the guage and I will check and calibrate it for you. I would drop the tank and check it there. You might have a pinched wire. those fuel tank senders are a wire wound resister with a slider on it. They are pretty tough and To be shorted don't sound right.

 

[ncbugeye]

I have the tank off and the sender removed from the tank already. Using an ohm-meter, the sender itself seems to be a dead short at any position of the float unit.

Methinks before I make a rash decision I will go get a new ohm-meter, this one is ancient, I have had it at least 25 years, it was cheap when I bought it, and it may be the problem.

How many ohms should the sender unit resistor be?

 

[jlaird]

Guys, I would point out that Kim is the resident expert on fuel gages and senders.

If he can not make em work, oh wait he always makes em work.

 

[spritenut]

90% of the dead senders I have taken apart have that thin wire fried off near the terminal. I have successfully reattached that wire and the sender worked again.
Well alot of them worked again but not all.
Hey, if it's broke, I'll at leaast try to fix it before I throw it out.

 

[ncbugeye]

Frank,

Thanks for that reassurance. I had the top plate off and looked at it, it is very clean inside and I didn't see anything broken, but tomorrow in the sunlight I will take another very close look at it, or maybe better still have my teenage son look at it as my eyes aren't as good as they were.

For reference I would like to know what the resistance should be, and at which end of the float's travel I should expect to find it.

 

[Sarastro]

90% of the dead senders I have taken apart have that thin wire fried off near the terminal. I have successfully reattached that wire and the sender worked again.
Well alot of them worked again but not all.
Hey, if it's broke, I'll at leaast try to fix it before I throw it out.

This is pretty much what I would expect. In most sender failures, the problem is an open circuit, not a short. Of course, anything is possible, but if you see a short, it's probably something simple like bad insulation allowing the wire to contact the case.

If you are using a digital multimeter, be sure the battery is OK, of course, but if the display shows an indication, the battery's almost certainly OK. Touch the probes together, you should get zero ohms; separate them, and you should get an infinite indication. If this happens, I wouldn't suspect the meter.

Be sure you have the meter on the right scale--if it is on a high scale, the relatively low sensor resistance might just read zero.

As for the resistance--I made some measurements of this at one point, but I can't seem to find them. If I remember correctly, the sensor is about 65 ohms, maximum, but don't take this as a certainty. It should be on that order, though; if you see 10,000 ohms or 1 ohm, obviously something is wrong.

 

[regularman]

Frank,

Thanks for that reassurance. I had the top plate off and looked at it, it is very clean inside and I didn't see anything broken, but tomorrow in the sunlight I will take another very close look at it, or maybe better still have my teenage son look at it as my eyes aren't as good as they were.

For reference I would like to know what the resistance should be, and at which end of the float's travel I should expect to find it.

It should vary between 0 ohms and 70 ohms or there abouts.