Fuel gauge intermittent

[19Fordy]

The frustration of trying to make King Sealy units work with the ohms style sending units is not just limited to Fordbarn.
Here are some other thoughts.
https://www.ford-trucks.com/forums/1209295-factory-resistance-values.html

I tried to measure the resistance of the calibration resistor found inside the KS units and the needle jumped all over the dial. Couldn't get a steady reading. Wonder if it possible to use a tiny variable resistor by wiring it into the KS unit and dialing in the resistance until the gauge responds properly? I also tried using a piece of graphite pencil lead and it did not work. Does anyone know if a zero ohm resistor would work?
Are there any Fordbarners with an electronics background who could devise a solution?

 

[rotorwrench]

KS has a different type of resistance unit on the older fuel quantity senders than they did on the later ones. The later ones had a small resistance spool but the early ones have it set up like a fuse holder so they could change them easily. They must have had quite a few different ones to pop in those things when they adjusted them at the factory. They likely color coded them or something but I just don't know. A person has to have some way to adjust it like a trim pot but I have no idea what the values (high and low) of the pot would have to be to make one work properly.

 

[JSeery]

The frustration of trying to make King Sealy units work with the ohms style sending units is not just limited to Fordbarn.
Here are some other thoughts.
https://www.ford-trucks.com/forums/1209295-factory-resistance-values.html

I tried to measure the resistance of the calibration resistor found inside the KS units and the needle jumped all over the dial. Couldn't get a steady reading. Wonder if it possible to use a tiny variable resistor by wiring it into the KS unit and dialing in the resistance until the gauge responds properly? I also tried using a piece of graphite pencil lead and it did not work. Does anyone know if a zero ohm resistor would work?
Are there any Fordbarners with an electronics background who could devise a solution?

These gauge and sender unit questions come up so often it would indeed be great if someone figured out a solution!

 

[B_man_Al]

The power and current values associated with the sender units are too high to to use a small variable resistor to calibrate the unit. Power dissipation can be as high as 1.2 W and .3A respectively at "full tank". Similarly a carbon resistor will likely be too big as well.