New Fuel Gauge Circuit

[Bitsyncmaster]

Thanks Dave. When you say you're driving the sender with 2.5V, are you referring to the FSU itself or the sender connection? And are you using a MOSFET to switch the gauge's Green/Black sender connection to ground, or are you driving it another way?

I don't switch the sender connection. I drive it with 5.0 volts through a resistor equal to the maximum sender resistance. Therefor I would read 2.50 volts on the green/black wire with full tank. (Some senders have the values swapped) I read the voltage on that green/black wire to determine the tank level. I guess you could switch that drive off and on to save a little power (10 ma. with a 250 ohm value at full and 17 ma. with the 40 ohm value at empty).

With the stock setup there is a lot more current flowing through the sender.