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I got a 1979 F150. I recently posted a question about the fuel sending unit not working right. I just got a NOS Ford sending unit to try. When I got the truck it had a new tank and sending unit in it. The tank looks to be the correct tank and it fits good. But the sending unit that was in it had a notch cut out so it could mount to the tank. It didn’t work right so I tried another aftermarket sending unit and it also needed notch cut in it. I figured maybe the Ford sending unit I just got would be shaped a little different so it would not need notched. But it is the same where it mounts to tank. Is this normal? Or does the truck have the wrong tank or just a cheap aftermarket tank that was not made right? Here is a photo showing where it needed notched next to the new one.
Ford one looks like it might be slightly smaller in diameter. The notch might be to engage a tab to turn it the correct way, where the Ford one doesn't?
Back up a bit.
Explain "Not Working Right"....
Sounding like changing the unit is not solving the problem.
The first one seemed to work but I found out it was very inaccurate. The second also worked but the gauge started only moving a little showing it having between 1/2 and 3/4 tank on the gauge. I was considering trying to bend it differently to see if it would move the gauge more. But I found the Ford brand one to try.
I would take all of the sending units, put them on your work bench and test each one individually.
Your issue may not be the sending unit. Could be a bad wire, a bad ground or a bad gauge.
I would take all of the sending units, put them on your work bench and test each one individually.
Your issue may not be the sending unit. Could be a bad wire, a bad ground or a bad gauge.
I tested them. The new Ford one is right on. The old one that was in it when I got it, which was supposed to be new, has ohm readings way off where it should be. The one that’s in the tank now was reading good before it was installed. I didn’t take the tank out yet. I will have to see what’s going on. The ground seems good. The wires are all new. I don’t know about the gauge. I have a new voltage regulator on the gauges.
I tested them. The new Ford one is right on. The old one that was in it when I got it, which was supposed to be new, has ohm readings way off where it should be. The one that’s in the tank now was reading good before it was installed. I didn’t take the tank out yet. I will have to see what’s going on. The ground seems good. The wires are all new. I don’t know about the gauge. I have a new voltage regulator on the gauges.
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Understood. The thing that has my attention is the one in the tank now "was reading good before installed"..... What happened?
If you remove the tank and check the one currently in the tank and it reads good.... Then your issue is elsewhere.
Is it possible to take readings while it is still in the tank. Maybe one with a full tank and one with 1/8 of a tank ?
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Understood. The thing that has my attention is the one in the tank now "was reading good before installed"..... What happened?
If you remove the tank and check the one currently in the tank and it reads good.... Then your issue is elsewhere.
Is it possible to take readings while it is still in the tank. Maybe one with a full tank and one with 1/8 of a tank ?
I’m going to do a lot of experimenting this weekend. I saw the NOS Ford one and decided to buy it. If I’m dropping the tank anyway it would be nice to put a Ford one in. I don’t have much faith in aftermarket stuff anymore.
I also posted this on another thread I started about this problem. I dropped the tank today. The sending unit was fried. I checked the voltage at the sending unit and it was 12 volts. It has a new voltage regulator at the gauge so it should be around 6 volts. Also, I put a test light on it and it did not pulse. So it must not be working. Is there anything that can ruin a new voltage regulator? Or maybe it’s just aftermarket junk.
