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Fuel Gauge Issue

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Old Mar 7, 2025 | 09:46 AM
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Fuel Gauge Issue

My fuel gauge only reads the first half of the tank. The gauge sweeps from full to empty, but when on empty there is still a half of a tank of fuel. I pulled the sending unit and it tested fine. What do I need to check next? This is for the rear 19 gallon tank.
 
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Old Mar 7, 2025 | 02:49 PM
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Check to see if the float arm is lowering near the bottom of the tank when empty. The arm can be bent to adjust reading at gauge.
 
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Old Mar 7, 2025 | 09:44 PM
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X2 what he said. 100% the float is good? Old brass or new plastic one?
 
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Old Mar 7, 2025 | 09:52 PM
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The sending unit is a new one with a plastic float that the previous owner installed when they replaced the tank. I checked the position of the arm when I had it out and the float sits even with the end of the pickup tube.
 
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Old Mar 7, 2025 | 11:21 PM
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Well like also said some times the spring arm gets bent when packaged/shipped/installed.
 
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Old Mar 9, 2025 | 10:17 PM
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Given that I am getting a good ohm range and the arm is in a good position I feel like I can rule out the sending unit. Is it possible that the cluster voltage regulator could be the cause?
 
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Old Oct 2, 2025 | 12:22 PM
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Is there a good rule of thumb when making adjustment, anyone done it when already in truck?

My new sending unit and tank are way off. Full is about 1/4 tank on gauge
 
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Old Oct 2, 2025 | 12:37 PM
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Does the truck have oil pressure light or oil pressure gauge in the cluster, and if a gauge, how is it acting?
 
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Old Oct 2, 2025 | 02:17 PM
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Coolant temp gauge works correct, will be hooking up oil pressure gauge when sender comes in this weekend.
 
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Old Oct 2, 2025 | 06:03 PM
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Blow out the gauge itself. Cobwebs may be holding it from full
 
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Old Oct 2, 2025 | 11:18 PM
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X2 blow it out with some very low pressure air or a compressed bottle of "canned air" like used on key boards. I know that you can adjust the gauge itself. Well make a adjustment to either side via a small hole in the back and some teeth on a arm with a small flat tip screwdriver. But it a tricky operation. Get the cluster to this part.

Notice that there is no rivets, the cover is crimped to the back round boody lip. Does not like to come off.

You can see the 2 arms and the slots that allow you to adjust. SO you do not have to take the fac plate off just get access to the back side of the gauge. And remember what direction to tun the arm. That MIGHT only chance the oms reading, I do not know. You can also see that there is already a cracked white piece around the threaded stud, that the nuts go on. The threads need to be held when you go to loosed the stud. DO NOTLET THE SHATF TURN,


When the stud breaks and fall out.


I have taken my fair share apart.

A guy just hade to Fast and Fusious his Ford truck in the dash dept.


 
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Old Oct 3, 2025 | 06:57 AM
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Nice,

If I pull the wire off sending unit and ground it, the gauge should sweep to full right?

Edit, yes, I confirmed this. Ground the positive and it will sweep to full
 

Last edited by KubotaOrange76; Oct 13, 2025 at 11:17 AM.
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