I have a 57 F800 with factory gauges. The previous owner put a 75 gallon saddle tank on it, and I purchased a universal fuel sensor for that tank. However, with the tank full, my gauge only reads 1/4 tank. I grounded the gauge and it goes all the way to full, and I checked the voltage at the sensor and it reads 3-5 volts. I know the ohms are different for the gauge and the sensor, but I do not know how to fix my problem, if it even can be fixed. Any help or suggestions? Thanks!!!

 

I’m thinking about trying the Tanks meter match. Any thoughts!!!

 

This looks like it should do the trick. MeterMatch Fuel Gauge Interface Module (tanksinc.com)

Also, a video to make you smarter:
Any pics of the big rig?

 

 

It is still a work in progress, and I will post more pics when I’m done with it.

 

That is a cool big job!