1957 fuel gauge is sluggish to reach the proper reading.

[Dave H]

When I first start my 1957, the fuel gauge pointer remains at empty, even though the tank has fuel. After about 10 minutes of driving, the pointer starts to rise. I'm never really sure when it rises to the level of giving an accurate reading, but it seems like it takes well over 20 minutes of driving (maybe even 30 0r more). Any ideas as to what would cause this, and what to do about it?

 

[zeroroadkill]

Have you checked the voltage at the sending unit and tested the grounding of the sending unit flange with a ohm meter? Same at the gauge end. Doug posted an article on how to test the gauge with a 9v battery.

 

[Tom Alpers]

I'd be inclined to suspect a bad constant voltage regulator. The part in the tank need do nothing different between sitting all night and after you start the car. Ditto for the wires. If you enjoy working on your back under the dash the CVR isn't too hard to replace.

 

[Sharecropper]

My '56 fuel gauge is also slow to move, although it starts moving immediately but very slow. My mechanic, a T-bird specialist, mentioned the CVR under the dashboard, saying it probably needs replacing. So far, I have been too lazy to replace it since I can live with the problem right now.

 

[dmsfrr]

My '56 fuel gauge is also slow to move, although it starts moving immediately but very slow. My mechanic, a T-bird specialist, mentioned the CVR under the dashboard, saying it probably needs replacing. So far, I have been too lazy to replace it since I can live with the problem right now.

A '56 didn't originally have a CVR. The '56 dash gauges & sensors were/are one-year-only parts and spec'd to work on full 12 volts. '57 was the first year Ford put in the CVR.

 

[Sharecropper]

Thanks for the reply. My mechanic is not as good as we think. I cleaned the ground wire at the tank when I had to replace the sending unit. Probably a cheap Chinese sending unit.

 

[Ed1957]

Have you checked the voltage at the sending unit and tested the grounding of the sending unit flange with a ohm meter? Same at the gauge end. Doug posted an article on how to test the gauge with a 9v battery.

The float in the tank is made of cork. Could just be old and soggy. Just a thought since nobody mentioned it.

 

[Ward 57]

The float in the tank is made of cork. Could just be old and soggy. Just a thought since nobody mentioned it.

I don't recall cork floats for many years. maybe in the model A days. most are made of brass and can develop leaks but then they will just fill up and never float.

 

[JudyBird]

Where can I get the wiring from fuel sending unit to gauge? TIA

 

[doug7740]

If your asking about a 1956 wiring diagram of the fuel sending unit, here is one from the Electrical Equipment Installation Manual and a section from the actual wiring diagram. Both can be purchased from any of the Thunderbird parts suppliers.

doug7740
1955 Thunderbird Blue

 

[JudyBird]

If your asking about a 1956 wiring diagram of the fuel sending unit, here is one from the Electrical Equipment Installation Manual and a section from the actual wiring diagram. Both can be purchased from any of the Thunderbird parts suppliers.

doug7740
1955 Thunderbird Blue

View attachment 30787

View attachment 30788

Thanks! But the wiring is missing and the new sending unit did not come with wiring.