I know i can "Tweek" a senders single with resistors for small changes with resistors in series with or to ground, but i'm wondering what would be a better way in changing the resistance of a 550-55ohm (Empty to Full) fuel sender to work with an 100 - 2ohm (Empty to Full) gauge.
Swapping out the fuel sender would work, yes, but that means getting one that works with the tank (Depth, opening, mounting)
The thing I dislike the most with Fuel Senders is they are Not Voltage regulated. So as the Battery changes a bit in voltage, So does the reading on the gas gauge.
The thing I consider a fuel (oil press, temp) gauges is just a variable needle based idiot light. Heck I had a car that the oil pressure guage was just that, there was just a resistor to put the needle in about the middle when the oil pressure switch closed when the oil pressure was above @10psi? Like really?!?! Least one can bypass the resistor and put a sender in to get a gauge that did something!
All and all the gauges as to the most part is just quick reference item.
Hi Kevin, Interesting question on modifying the sender - can you give us a little background on why you want to use the 100-2 ohm gauge? Is this for a car or truck, gas or diesel, etc? As Gary pointed out, replacing the sender is about the only viable resolution. Cost-wise (and time-wise), you'd probably be better off with an OEM replacement sender or gauge, or both, unless you can somehow economically modify the sender to use a 100-ohm wire-wound potentiometer and get it to fit in the gas tank. Doing the math, there is no single resistor that can be placed in parallel with the sender's internal variable resistor (550-55 ohms) to give it a 100-2 ohm range.