The Stovebolt Site Forums The Shop Area The Electrical Bay 12 v fuel Gauge

I just bought a 12 v fuel gauge from orange truck shop and as soon as I installed it in the cluster and back in the dash long behold The Needle when all the way passed the E and I can’t even see the needle any more. Is this normal for these fuel gauges?

Do a search on the site for the most accurate fuel gauge for AD trucks discovered by John G. Sells on ebay for $30.

And I've never seen my needle go that far even when the tank was brand new and empty.

Before you go and waste money away throwing parts at it, troubleshoot. There is a troubleshooting procedure I wrote, that is a sticky thread at the top of the electrical forum. Here is a [LINK].

Hi folks. Your fuel gauge cares much less about voltage than you might think. After a long and involved study of these (and some other balanced magnetic schemes), I can tell you 12v will only harm your fuel gauge in one particular aspect: there is an hourglass shaped permanent magnet at the base of the needle in your fuel gauge...this is very important in determining the accuracy of your gauge. I've written about this before and I've posted images of it here. If your gauge has been run on 12v the magnetism of that hourglass shaped piece of metal will be changed...increased, actually. And nobody has any way of telling us how long it will take...there are too many important variables. Some people think it could only take a few hours and some think it could take about 1 day. This means it (your gauge) will never again register correctly if run on voltage less than 12...but your fuel gauge won't be burned out. So for anyone buying a Runtz device, it is probably not necessary. However, if you think you want a voltage reducer, please send me a PM or an email and we can talk. I made a sophisticated but small voltage regulator a couple of years ago. It is adjustable from about 2v up to 12v and tolerates amperage up to around 2 amps. You simply install it (just like the Runtz). Then adjust it with a tiny screwdriver so that your fuel gauge registers F when your tank is completely full and when you know your fuel gauge sending unit is working correctly and your gauge circuit is wired correctly and grounded correctly. And then you're done.

Also...Some have said the AD fuel gauge isn't any good. Some have said it was never accurate in the first place. In my experience it is actually a well-designed gauge capable of impressive accuracy and very long life. On the other hand the AD fuel gauge sender was designed to fail right from the start. It only had one wobbly pivot point and the case was made of cheap potmetal...which allowed it to wear out very rapidly. And when the case inevitably wore, the float arm would rub against the narrow sides of the tank. A bad recipe. Looking at it, I doubt any of the senders lasted more than 5 years. Some of you may recall I re-engineered the original sender adding an extra pivot point and making it work again.

Yes! Thank all of you, I’m going to trouble shoot first and then proceed on getting a new one if so. I’ll keep you guys post.

Ok thank you...

This does not address your issue but my new 12v fuel gauge goes way past the full mark when I fill it up. Once the fuel level drops to between 1/2 a tank and 3/4 of a tank the needle drops back and reads fairly accurate the rest of the way to empty. I have not taken the time to trouble shoot it yet but these gauge can do some strange things.

If you bench tested your new gauge before installing, then it's pretty simple to remove your sender and test the float.
With the float removed but connected, (use a jumper to your ground post), turn your key on, then manually move the float.
If it works, bend the arm a little.
If it doesn't work, buy the sender that JonG likes.
If you didn't bench test your new gauge first... use Pkak1's troubleshooting guide.
.

This one.

https://www.ebay.com/itm/261122347319?hash=item3ccc1ad137:g:FBgAAOSwpPVgBuwZ&vxp=mtr