Mil1ion
Still Da Man
After doing some research...This needs to be in here.
Re: Ford Gauges
They are calibrated to read empty or zero at 70 Ohms of resistance. The full or maximum reading will be at 10 Ohms. All of the senders are calibrated for this 70-10 Ohm range. The fuel sender at 1/2 tank should read 40 Ohms.
~Ohms >> Reading
150 >> No movement - same as if the wire were broken or disconnected
73 >> Off scale 1/2 needle width below E
68 >> E
50 >> 1/8
26 >> 1/2
15 >> 7/8
12 >> F
10 >> Off scale a needle's width above F
Since the gauges are all a little different these numbers are not exact, but close. Shorting the sender wire to ground is a way to test the gauge but since its Zero Ohms to ground it will be overheating the gauge if you keep the short there for very long.
Even with an empty tank the needle will move just a bit when the key is turned on so that it is at the 73 Ohm position. That tells you the wire is not broken. With the 16 gallon tank and an original Ford float properly adjusted the first 1.5 gallons does not change the gauge reading; Ford's way of getting you to fill up early so you won't run out of gas. Likewise the last gallon does not change the slightly more than F reading; makes you feel good that the needle didn't drop after the first 10 miles of driving.
Re: Ford Gauges
They are calibrated to read empty or zero at 70 Ohms of resistance. The full or maximum reading will be at 10 Ohms. All of the senders are calibrated for this 70-10 Ohm range. The fuel sender at 1/2 tank should read 40 Ohms.
~Ohms >> Reading
150 >> No movement - same as if the wire were broken or disconnected
73 >> Off scale 1/2 needle width below E
68 >> E
50 >> 1/8
26 >> 1/2
15 >> 7/8
12 >> F
10 >> Off scale a needle's width above F
Since the gauges are all a little different these numbers are not exact, but close. Shorting the sender wire to ground is a way to test the gauge but since its Zero Ohms to ground it will be overheating the gauge if you keep the short there for very long.
Even with an empty tank the needle will move just a bit when the key is turned on so that it is at the 73 Ohm position. That tells you the wire is not broken. With the 16 gallon tank and an original Ford float properly adjusted the first 1.5 gallons does not change the gauge reading; Ford's way of getting you to fill up early so you won't run out of gas. Likewise the last gallon does not change the slightly more than F reading; makes you feel good that the needle didn't drop after the first 10 miles of driving.
