fuel gauge error

[1970f100x]

My fuel gauge doesn't seem to be accurate. I didn't think anyhthing of it until I actually filled my tank full, and it only said i had 3/4 of gas, when it was overfilled. Now it says im empty when I have like 2 gallons in it or more. Whats the deal?

[BobbyFord]

Possible float filling up with gas. Pull the sending unit for inspection. Floats are available but sending unit is only available aftermarket.

[1970f100x]

Possible float filling up with gas. Pull the sending unit for inspection. Floats are available but sending unit is only available aftermarket.

could i see a diagram or picture of this thing.

[fordman]

behind the seat is the gas tank. on top of the gas tank is a round object. with about 6-8 screws holding it to the tank. remove thoise screws and the wires. pull the disc up out of the tank. you will see the whole sending unit come up out of the tank with the plate. the last thing to come out with is the float. before you do that though. check out the fuel sending unit tech page. and test the sending unit and maybe adjust the ipvr if needed. http://www.fordification.com/tech/fuel- ... -units.htm

[knightfire83]

I had the same problem with both my tanks. My fix was to fill a tank completely and adjust the instrument panel voltage regulator till the fuel gauge read full. This will also raise the needles on the temp and oil psi gauges.

http://www.fordification.com/forum/view ... &hilit=ivr

[BobbyFord]

C1TZ-9275-K, Page 39...

http://www.dennis-carpenter.com/pdf/67-79_2009.pdf

[1970f100x]

Ok, the problem is definately the ipvr, I took it off and I couldn't see how you adjust it? Can anyone help me on that?

[Montana71-F100]

I had the same problem. Mine would only read a little over 1/2 full when the tank was full. There is a tiny screw that can be turned. I can't remember exactly where it is. There may be a small hole you have to put a small screwdriver through. Your gauges are 6 volt and your system is 12 volts so the regulator pulses the 12 volts on and off to give an average of 5 volts. (Too many 6 volt gauges on the shelf when the industry switched to 12 volts.) I'm guessing the screw adjusts the tension on a spring to allow it change the average number of volts. Mine read 4 volts and It's supposed to be set at 5 Volts but I adjusted mine until it read 6 volts on my multimeter and quit because I was afraid to give it more current. I also took my sending unit apart and saw that there was no wear on the rheostat on the "full" end so I bent the tabs that stop the float until the movement of the float made contact with that part of the rheostat. Now, if I spend a lot of time almost dribbling gas in the tank, I can get a full reading but I'm usually not that patient and I can only get a reading of a little over 3/4 of a tank.

[1970f100x]

yeah, I have a 70 f100, and I just need to know exactly how to adjust it, because its def. an ipvr.

[Montana71-F100]

I found a picture on e-bay

[1970f100x]

I found a picture on e-bay

so i have to take off that cover thing?

[Montana71-F100]

You don't take the cover off, you take the whole thing off. It's attached with two snaps. If I remember right, it is attached to a thin flat flexible sheet. I used a flat screwdriver to verrrry carefully pry it off. Then turn the screw in tiny bit to increase voltage, then put it back on and test it with a multimeter. I attached my multimeter to the sending unit on the top of the gas tank to test it. I'm no expert, that's just what I did. It's supposed to give a 5 volt reading. I tried that first. My gas guage was still off so I went to 6 but was affraid to go any further. I didn't want to ruin my gauges. That voltage regulator will affect all of your gauges. My oil light was going on when it shouldn't.