Miss-matched fuel tank sender to fuel gauge... Help Needed

[deenz]

I am a total novice and need some help, or perhaps pointing in the right direction, please...
I had a faulty fuel tank sender on my boat and sourced a replacement (not an easy task as it has an odd fitting)... I installed the new sender only to find that it sends a signal in reverse to that of the original - so when the tank is full the gauge reads empty and when empty (not a good idea on a boat) it reads full... Just swapping the wires does not work. So my question is.. is there a piece of electronics that I can source or have made that effectively takes the input from the sender and reverses the signal strength? Many thanks in advance for any solutions...

 

[MikeMl]

It will take some electronics, like an opamp. Worse, you will have to generate a sender resistance vs gallons added to the tank plot from empty to full. You may also have to determine how much resistance causes the meter to read 0, 1/8/14,...7/8 and full

 

[BioniC187]

How many wires does your gauge have?

 

[cowboybob]

Welcome, deenz!

Try reversing the wires on the gas gauge.

I should add that that this may daamage the gauge if there are any electronics (a populated PCB, for instance) attached to the back of the meter. I am assuming the gauge is just a meter with two screw terminals.

 

[crutschow]

To start we meed a measurement of the gauge resistance and the sender resistance at both full and empty.

Alternately it might be simpler to buy a gauge that operates properly with the sender.

 

[KeepItSimpleStupid]

From my car experience, there is some sort of regulator. The one's I dealt with were external. Sometimes, they "pulse" at a lower voltage and use an "milliammeter/uAmmeter" with a fluid to minimize power dissipation.

You can always replace the gauge too: https://www.wemausa.com/gauges/level.shtml#Fuel Note: customization is possible, They claim 240 to 33 ohms is the US standard, but don;t tell you which one is empty.

 

[mel8030]

You might be able to unfasten the resistor and remount upside down, then bend the arm wire to obtain the original swing function. Or even repair the old sender as in this link:
**broken link removed**