The fuel sending unit in my car operates within a range of 10-520 ohms. I want to replace this unit for one that runs in a range of 0-90 ohms. I'm assuming I will need something to compute the change, but I'm not sure where to begin as I'm not versed in electricity. Can someone help me out? Thanks in advance!
Where do you have these numbers from? Datasheet?
You could measure the resistance, calculate the corresponding value and pass it on to an Digital potentiometer. If you have some coding experience on Arduino or similar, this is a days work.
But I am quite certain, that there is a simpler way. But to figure out what works, you would have to find out how the resistance is measured. Is a constant current flowing through the sensor? Or is it part of a voltage divider?
Try to measure the following: How much current flows on "empty"? How much current flow on "full"?