I finally got tired of the Year One fuel sender reading being way off, my 1973 Dusters' fuel gauge going from F to E in 125 miles with 75 to go in the tank, and having to think about it.
I finally got around to getting an auto meter fuel bridge calibrator and a #2652 Z series fuel gauge.
The installation itself is no big deal, I already did it with my Z series 5000 rpm tach and oil pressure gauges. But calibrating this fuel bridge to the sender and gauge has me thinking. Their procedure could be improved. Biggest problem is you start with the tank FULL and go every 1/4 tank until you get to Empty. If you started with Empty and just put in 4 gallons for each 1/4 tank setting (in the case of a Duster gas tank), until you got to Full, it'd be a lot easier.
So I was thinking how I could not put 16 gallons in the tank and take out 4 at a time. My Duster is sitting now with the tank empty, I guessed it just right and got it home right on E, and then with the car backed onto a slightly downhill piece of ground, it stalled out from the gas flowing to the back of the tank.
My big plan is to get my multimeter and take resistance readings right at the tank, then fill it with 4 gallons, take a reading, 4 more gallons, take a reading, etc.
Then get a 0-100 ohm potentiometer and connect it to the wire and ground leading to the fuel bridge, and calibrate it in order, full to empty. I think that'll get it pretty close. As I go through each step, adjust the potentiometer to give the same reading the sender unit did at each fuel level.
If anyone downloaded the pdf of the calibration procedure, I am doing it on the 4B section for a custom fuel sender in the 0-1000 ohm range, since I'm using a replacement BG914 sender from Year One.
https://www.yearone.com/Product/chrysler-a-body/bg914
I'll be paying attention to grounds and wire connections, don't want extra resistance throwing it off.