Hi, I have a 57 88 and have installed a new fuel tank and sender and can't get the gas gauge to work, there is power to the circuit board and the holms tell me the sender is working, I was told the gauge was bad so I bought another and it didn't work either.


any ideas?
Thank you.

 

What happens with the gauge needle when you disconnect the wire at the sender and turn the ignition key on? Does it go to or past the full mark? If you ground the same wire the gauge should go to empty with the key on.

 

X2 check for a bad ground. If a 57 is like a 55 the ground is the gas line. If there has been a repair done to the gas line and a rubber hose was used as a splice the ground has been interrupted ...... Tedd

 

Thank you!


I think Tedd may have something here, an early 70s 455 was installed before it bought the car, it has an electric fuel pump with mostly rubber lines from the engine compartment to the carburetor. If the old metal line was the ground where would it connect to the circuit board? do you think I could run a ground wire from the sender to a post on one side of the gauge?


Thank you,
Brett

 

Not familiar with yours, is there a separate ground lug on the sender? If so, you can run a ground from there to the chassis. Did you perform the test above, as it will isolate your issue to the sender or the gauge and wiring?

 

Eric,


I did run a separate ground when I put the new gas tank in and ran it to the license plat mount, I just disconnected it and ran it to the bumper mount for a better ground and it didn't change anything. I haven't done the test you suggested YET partly because the same issue was here before I changed the tank. that's why I am thinking it might be what Tedd said about the fuel line being the ground. Do you think I could run a wire from my extra ground to one side of the gauge? if so what do you think would happen?


thank you,
Brett

 

It sounds like you probably have the tank grounded. Take an ohmmeter and check the tank to the frame to be sure. The possibility could be a problem with the wire from the sender to the gauge. It could be broken and open or it could be shorted to ground. I see no reason to run a ground wire from your sending unit to the gauge. These old gas gauges are pretty simple but can be a pain to get to work right. The one in my 54 has a mind of it's own.

 

I tested from the tank to ground and got no reading so I think it's good. and then I found a bad connection in the trunk from the sender, I fixed it and tested the ohms there and got 1180, then tested at the back of the instrument panel, I put my + lead on the stud from the gauge and the - to ground and got 1390 (the tank is full) but still had no reading on the gauge. UGH.

 

Again, perform the test that I suggested, it will make sure all the wiring and the gauge is good, or not. If we can eliminate everything forward of the tank, the rest is easy.

 

OK, I will as soon as I can Eric, Looks like the best way at this point.


Thank you,
Brett

 

Hi,

I have a 57 2dr post 88, and have installed a new fuel tank and sender, the wire under the dash shows the sender is working, but the gauges doesn't work when I hook it up. Someone told me they had a voltage reducer back in the day, so the gauge didn't bounce due to the fluctuation in voltage?

Any thoughts?

Thank you,
Brett

 

It's true that some manufacturers utilized a voltage "reducer" to operate some of their gauges on, to insure better accuracy as system voltage varied (I have an AMC and Ford that are this way), however I cannot find evidence of such on the '57 Olds. The '56 Olds Shop Manual says "The gauge is compensated for temperature variation and is not affected by variation in voltage of the battery". Similarly the '57 shop manual shows no indication of a voltage controlling device either in the wiring diagram or the text. The fuel gauge appears to be fed via an SFE 9 amp fuse in the panel. In the '57 shop manual on pages 13-26 and 13-27 there is a fuel gauge testing procedure shown utilizing Borroughs testing device BT-100.

 

I merged your new thread with the old one for the history of what you have done. Have you tried grounding the wire that runs from the gauge to the sender with the ignition key on to see if the gauge goes to "E"? Removing the wire so it is not connected to anything will drive the gauge needle to/past "F". Doing this will isolate your problem, because the wiring from the tank to the gauge, and the function of the gauge is fine, the issue is at the sending unit.

 

Thanks for merging my threads! I tried your test and when I removed the sender wire it stayed on E, when I grounded the sender wire it barely moved off the E.

 

Do you have voltage at the gauge? Remove the sender wire from the gauge the needle should go to past F, ground the post where the sender wire connected and it should go to E.

If you have voltage and the above tests fail, the gauge is bad.

 

Defective gauge?????????

 

Good afternoon, I found this post from a few years ago. I am dealing with my 1957 Oldsmobile 88 fuel gauge and sender issues. The gauge rests at empty with the key off. With the key on it reads between 1/4 and 1/2. If I disconnect the gauge from the sender, the gauge reads full (key on). If I ground the gauge, it reads between 1/4 and 1/2 (key on). The voltage between the gauge and the end of the line to the sender connection (disconnected) is 3.72 V. The resistance measured at that same connector is 363.8 Ohms and the resistance for the sender line to the sender is 0.0 Ohms (though I had other readings of 1.7 and 0.7 Ohms). The tank is almost full. I believe the sender may be stuck and the gauge may also be faulty. I would have guessed the sender would have a resistance reading of 24 to 27 Ohms if it was correctly measuring the tank fuel level. I don't know if the voltage and resistance readings in the gauge wire suggest something other than the gauge being faulty. I hope someone can help. Thanks, David
I should have added that I believe the car sat for many years as the mileage in 1969 was 67,160 and in April 2025 is was 74,055 - not even 7K miles in 56 years.

 

If I were you I would start with the sending unit in the tank. After all the work I did to replace the gauge on mine, it still ended up being the sending unit. The float on the arm was made of cork and completely soaked from years of sitting in the tank. I hope that helps!

 

My thought is to get a new sending unit and use it to test the gauge. With this said, I am not sure the gauge would act much differently from the readings I am currently getting. I am wondering about too little voltage from the gauge and whether it should be as low as the 3.72 V I measured? Thanks, David