1957 Ranchero fuel sending unit assistance

[slopokpete]

I recently was able to fill the gas tank on my 1957 Ranchero.  I wanted to check the function and accuracy of the sending unit before I installed the bed floor.
The gauge was reading on the low side ie. gauge read slightly above 3/4 with full tank.  I thought no problem I'll tweak the float arm and should be good to go.  As it turns out it didn't change the reading.  With the unit out of the tank and the float at the full position I got the same result.
I checked the resistance of the sending unit and it is 106.4 ohms at empty and 14.9 ohms at full.
Does anybody know what the factory specifications should be?
If there was a way to reduce the resistance slightly at full the gauge should read accurately but it's easier to add resistance than to reduce it.
I imagine that the available sending units probably come from a single source.
The car has a new ClassTech wiring harness and the gauge will show full when I briefly ground the sending unit wire.
Any advice or suggestions would be appreciated! or maybe just condolences

Thanks
Jeff

[RICH MUISE]

The ohms don't sound quite right, and I believe the sending unit is supposed to be grounded, but I'm depending on my bad memory, assuming they're set up the same as a passenger car. Check out  www.tanksinc.com  They have a great troubleshooting guide for sending/gauge circuits, and tell you what the ohms are supposed to read for our (and all ) cars..
I was checking the link I gave you, and it is correct. I read this while I was on there:
Because the gauge is reading a resistance to ground having proper grounding of the sending unit is essential to get an accurate reading on your fuel gauge.

[Ford Blue blood]

The fuel tank sending units used on all Ford products up through 1986 have a resistance range of approximately 8-12 ohms full and 70-73 ohms empty.

Found this for info.  Make sure the sender is grounded.  I always use one of the screws that hold it to the tank as a ground source.

[hiball3985]

 rancheros/wagons don't have screws, I use a jumper wire.

[lalessi1]

Tanks Inc makes a Meter Match that I use. I allows you to make the gauge read full at the resistance it is putting out when the tank is full. It is adjustable at E and several mid-range settings as well.

https://www.tanksinc.com/index.cfm/page/ptype=product/product_id=748/category_id=-1/mode=prod/prd748.htm

[RICH MUISE]

If Slopoke comes back, I wanted to ask if he was using the OEM gauge. And, as Bill mentioned, 70-10 Ohms is what Tanksinc lists.

[slopokpete]

Thanks for all the info, yes I'm using the stock gauge and I did see the gauge/sending unit matching device that Tanks offers.
It would appear that I have a less than accurate reproduction sending unit!

Jeff

[mustang6984]

Jeff...can we see pics of this project?  PLEASE?

[slopokpete]

I'll give it a try!

I apologize for the size of the photos.  I'm not certain how to resize them

[terry_208]

Nice!

[KYBlueOval]

Very Nice!

[hiball3985]

Super nice

[57chero]

When you say you have a less than accurate sending unit I'm not aware of anybody reproducing the Ranchero/wagon sending unit, are you using one for a car?

[mustang6984]

Very nice! I see you have a thing for yellow eh? LOL!!!
Nice ride!

[RICH MUISE]

Beautiful........thanks for posting.