[19Fordy]

Originally Posted by randy993

When I replaced my tank I installed an aftermarket sending unit. At the time there were several to choose from that varied in OHM range. I went with "ORG - Early Ford & Mopar - 73-10 Ohms" . I got a voltage reducer and hooked up the guage. I checked it first by grounding it and it went straight to full so I believe that the guage is working properly. When I hooked up the sender wire it also went to full, just slower. My tank on my truck should be close to full so I'll just have to drive it some and see how it reads. I believe that i adjusted it correctly when I installed it.

The OEM gauges do not operate on an OHMs principle. Therefore an after market sending unit that operates on the OHMs principle will not work accurately with your OEM gauge. In order to use your OEM gauge you will need to install a "matching" King Sealy sending unit that Ford used.

To get accurate data, remove the gas tank sending unit when youR gauge registers FULL, 3/4, 1/2 1/4 and E and measure the depth of the remaining gas in your tank so that you can calculate how much gas is still in the tank at each reading.

For instance, when you measure the depth of the gas in tank when the tank is full you might find it's 9 inches deep with the 14 gallon tank.

Then when the gauge reads 3/4, again remove the sending unit and measure the depth of the gas in the tank. Let's say that measurement is 7 inches on your ruler. Then use the following ratio to find out if the amount of gas remaining in the tank is really 3/4 of the tank's 14 gal. full capacity.

9/14 =7/X X=10.8 gal. actually LEFT in the tank.

Three quarters of 14 is 10.5 gal. So your 10.8 gal. finding is pretty close.

Follow that same procedure at each of the the markers on your gauge to verify the sending unit is providing accurate info. to your gauge.

Pay special attention to the reading when your tank measurement is close to empty.

This process takes a while depending on how frequently you drive you car but, it's worth the time spent.