Ohms, Volts and Fuel Gauge Operation on P15

[kbuhagiar]

Hello Folks,

 

I am in the process or re-wiring my modified 47 Plymouth. The car had already been changed over to 12 volts when I got it.

 

Although the factory fuel gauge was operational, it has never been particularly accurate. I've just discovered that the gauge was fed a straight 12 volts (not reduced).

Is it safe to say that this would have affected its accuracy? Would the gauge be damaged by the increased voltage?

And, if memory serves me correctly, the resistance range of the factory fuel sender should be 0 ohms (empty) to 30 ohms (full), correct?

 

Thanks in advance.

[Plymouthy Adams]

the fuel gauge has a built in voltage regulator...while it can operate on 12 volts it may indicate the higher voltage by a flickering needle due to the faster cycle rate of the VR...the 12 volts I still do not recommend since it is so easy to reduce the voltage back to the optimal 7.2 volts as is the output of the generator when functional at normal input.  approx. 28-32 ohms across the sender is correct.

[Andydodge]

I can't give specifics re the ohms but I have had a standard 12 volt resistor, the same type that is used in a 12volt ignition circuit wired up to the Fuel gauge in my 318 Poly powered 1940 Dodge for about 45 yrs........the gauge has never been 100% truthful but it certainly shows when full or empty and variations in between..........andyd.