The Ford Barn

19Fordy · 09-26-2017, 03:45 PM

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/1...ce-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 · 09-26-2017, 05:18 PM

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 · 09-26-2017, 05:23 PM

Quote:

Originally Posted by 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/1...ce-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 · 09-27-2017, 07:26 AM

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.

09-26-2017, 03:45 PM	#41
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,925	Re: Fuel gauge intermittent 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/1...ce-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? Last edited by 19Fordy; 09-26-2017 at 03:53 PM.

09-26-2017, 05:18 PM	#42
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,425	Re: Fuel gauge intermittent 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.

09-27-2017, 07:26 AM	#44
B_man_Al Senior Member Join Date: Feb 2011 Location: Ottawa ON Canada Posts: 301	Re: Fuel gauge intermittent 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.