The Ford Barn

Seth Swoboda · 03-20-2012, 11:15 AM

My fuel gauge in the 39 pickup is no longer working. I am using the original Ford sending unit. I bench tested this unit before I put the tank back in the truck and it worked fine. After placing the tank back in the frame and mounting the bed, I put some gas in the tank and the gauge was working (came up a bit). Recently the gauge no longer is working.

I am running 12volts with the NAPA IR1, voltage drop/regulator, on the stock gauges. My gauge is also new. When I put a volt meter on the power feeding the voltage drop/regulator I get 12 volts as one would expect. When I test the output side of the voltage drop I get a pulsing 6 volts. Meaning the meter will jump from zero to 6 volts in a consistant pulsing rythem. When I test the volts on the fuel gauge I get the same pulsing activity. When I go back to the tank at the sending unit I get the same pulsing activity. I get the same result when I checked the volts on the oil pressure gauge. The oil pressure gauge works fine.

Do you guys have any ideas what could be causing my fuel gauge not to work? I have power everywhere, although it is that pulsing 6 volts. The gauge was working before and now it reads empty (yes there is fuel in the tank, approx 5 gals). Do I have a sending unit problem, fuel gauge problem or somthing else acting up?

I don't want to debate 12volts over 6volts just figure out how to get my gauge working again.

Thanks for your input guys,
Seth

19Fordy · 03-20-2012, 11:47 AM

I bet the problem is the voltage reducer you are using. Shouldn't the output from the reducer be a continuous 6V, instead of pulsating. I am not an electrical whiz, but perhaps you need a CVR (constant voltage reducer). I am using the Ron Francis CVR. It puts out a steady 6V. http://www.ronfrancis.com/prodinfo.asp?number=VR-1

Charlie ny · 03-20-2012, 08:20 PM

Sponsored Links (Register now to hide all advertisements)

Seth,
If all else fails remove the sender and hay wire 6v to the fuel gage
and see what happens. Although it is a no no in desperation I used a NAPA 12 v
to 6v reducer ( one of those round ceramic ones ) after trying the special reducer
then runtz units with questionable success. My gages work fine and have for 10
months. If you need a dash gage email me off site I've got a ton of them. As you
know the OP and fuel dash gages work the same at least for test purposes.
Charlie ny
[email protected]
Charlie ny

03-20-2012, 11:15 AM	#1
Seth Swoboda Senior Member Join Date: May 2010 Location: Southern Illinois Posts: 3,788	Fuel gauge/sending unit not working in 39 pickup My fuel gauge in the 39 pickup is no longer working. I am using the original Ford sending unit. I bench tested this unit before I put the tank back in the truck and it worked fine. After placing the tank back in the frame and mounting the bed, I put some gas in the tank and the gauge was working (came up a bit). Recently the gauge no longer is working. I am running 12volts with the NAPA IR1, voltage drop/regulator, on the stock gauges. My gauge is also new. When I put a volt meter on the power feeding the voltage drop/regulator I get 12 volts as one would expect. When I test the output side of the voltage drop I get a pulsing 6 volts. Meaning the meter will jump from zero to 6 volts in a consistant pulsing rythem. When I test the volts on the fuel gauge I get the same pulsing activity. When I go back to the tank at the sending unit I get the same pulsing activity. I get the same result when I checked the volts on the oil pressure gauge. The oil pressure gauge works fine. Do you guys have any ideas what could be causing my fuel gauge not to work? I have power everywhere, although it is that pulsing 6 volts. The gauge was working before and now it reads empty (yes there is fuel in the tank, approx 5 gals). Do I have a sending unit problem, fuel gauge problem or somthing else acting up? I don't want to debate 12volts over 6volts just figure out how to get my gauge working again. Thanks for your input guys, Seth

03-20-2012, 11:47 AM	#2
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,930	Re: Fuel gauge/sending unit not working in 39 pickup I bet the problem is the voltage reducer you are using. Shouldn't the output from the reducer be a continuous 6V, instead of pulsating. I am not an electrical whiz, but perhaps you need a CVR (constant voltage reducer). I am using the Ron Francis CVR. It puts out a steady 6V. http://www.ronfrancis.com/prodinfo.asp?number=VR-1

03-20-2012, 08:20 PM	#3
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Fuel gauge/sending unit not working in 39 pickup Sponsored Links (Register now to hide all advertisements) Seth, If all else fails remove the sender and hay wire 6v to the fuel gage and see what happens. Although it is a no no in desperation I used a NAPA 12 v to 6v reducer ( one of those round ceramic ones ) after trying the special reducer then runtz units with questionable success. My gages work fine and have for 10 months. If you need a dash gage email me off site I've got a ton of them. As you know the OP and fuel dash gages work the same at least for test purposes. Charlie ny [email protected] Charlie ny