Spitfire Fuel gauge

[number6]

Since I got my Spitfire ( Sabrina ) I have had a consistently low reading fuel gauge. Full tank, gauge reads just below 3/4 full. So far I have replaced the gauge 3 times, swapped
The voltage regulator and inspected the fuel float, which is intact. Float arm is free and has full range of motion. Grounded the sender wire and still get the same result. I am beginning to believe that the wire between the tank and gauge has an issue. Thoughts and suggestions would be welcome at this point. Next step I guess would be to run a new wire between
and see if that makes a difference. Not a big deal really, but one of those small things that bothers me.

 

[Gliderman8]

Did you check to make sure the float doesn't have fuel in it?
Over time the plastic floats can leak.

 

[TR3driver]

What happens if you ground the wire to the sender at the gauge? If that takes it to full scale (note that it takes some time for the gauge to fully respond), then there is likely a problem with the wiree to the sender. Otherwise, I would guess a problem with the wire to the VS. Check the power right at the gauge if you can.

 

[number6]

I appreciate the suggestions and will try them. The float is completely empty. I'll give the results as soon
as I can get back to car.
Thank you, Tom.

 

[dklawson]

With the Spitfire, you can remove the sending unit from the tank and leave its wires connected. With the ignition on, move the float arm slowly through its full range of motion. If you move the arm all the way "up" does the gauge go to "full"? If not, disconnect the two wires and with the arm fully up, measure the resistance across the two sending unit terminals. When the arm is fully up the resistance should be close to 30 Ohms.

Let us know what you find doing these tests and the others suggested above.

 

[Andrew Mace]

I almost wonder if this might be an issue with the voltage stabiliser; how is the temp gauge doing?

 

[number6]

Andrew, interesting observation, I hadn't been taking notice of the temp gauge. But it does read slightly higher with the different stabilizer. I did ground the wire at the gauge and needle did go almost all the way to full. Both of the stabilizers were ones I had kicking around, sooo, I am going to order a new one. Since I am in the middle of this I think it would probably be a good idea to replace the sender
as well. Stay tuned for more, same bat time, same bat channel.

 

[dklawson]

Do not spend money on a new stabilizer yet unless you just want to have a more modern one.

If both fuel and temp gauges were reading high, or both were reading low, that suggests looking at the voltage stabilizer. However, in your case, with one gauge reading high and one reading low, that suggests a problem with the sending units or gauges... not the stabilizer.

 

[number6]

It's reading closer to full than it was, I can live with that. Appreciate all the hints I have been given. Thank you, everyone. Always good to have extra insight.
Tom s