Inaccurate fuel level readings

[wptorres]

Hey all!

I've got 2024 F150 with the 5.0L and the 36gal fuel tank. I've noticed that, since new my truck will read a "full" tank for around 150 miles, or 8 gallons, before the digital guage begins to drop. It bugs me that this guage isn't an accurate representation of how much fuel I have left, and I'm curious if there's any way within forescan to adjust/calibrate this so it's actually accurate? My hope would be that at "3/4" tank on the guage I'd actually have 28 gallons left; 20 at "1/2", 12 at "1/4", etc. (accounting for the 4 gallon reserve). Any ideas if there might be a way to adjust or recalibrate this, or am I just going to have to live?

For reference, a family member also has a '24 F150 (2.7L), and theirs is nowhere near as exaggerated as mine. It'll only stay on full for the first 75~ miles/4 gallons.

Thanks in advance for the help!

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[SilverPigeon]

I never actually take notice of the graphical fuel gauge, but instead the DTE value. In FORScan you can change the way DTE is calculated, but before mucking around with that (it's a decent algorithm already and shouldn't need changing) I would adjust AFE bias in Engineering mode to properly reflect real fuel economy instead of the reported which is always optimistic. This will affect the DTE value displayed and will make it more accurate.

To do this, you will need to hand calculate your fuel economy. Better to have multiple hand calculations for a realistic average.

So, if your '24 is the same as my '23, to get into engineering mode start with the truck in normal drive mode, all doors etc. closed to avoid messages on the cluster. Turn the truck off. Hold down the OK button on the steering wheel and start the engine. Let go of the ok button when you see the engineering mode message. Use the scroll buttons on the steering wheel to get to AFE bias.

By default, AFE bias is set to 1,000. If your actual economy is worse than reported by the truck, you need to lower the number (it's a multiplication factor). For example, my truck reads true by setting the number to 964. Fine tune your AFE bias by continuing to hand calculate economy for comparison.

 

[Risky Bizness]

Our 2024 F150 King Ranch had a guage problem at 529 miles. I'm including a list of the parts installed to correct it.

Problem found was corrosion in the fuel pump connector and pump assembly.

Here's the list:

9002A6------$34.40
12650D--------34.40
12650DX1------17.20
12651D45------51.60
MT14S411------68.80
LU5Z9276A-----14.27 (Gasket)
3U2Z14S411DGAC--71.25 (Wire Assembly)
PL3Z9H307H--341.34 (Sender and Pum)

Labor 206.40

The tech told me that the main problem was that a connector was never snapped completely together which led to false/inaccurate readings that read anywhere from 0 miles to empty to showing a full tank. Tank had to be dropped to make repair.

Sorry that the parts list doesn't show the name of the each part, but that's the way the ticket is/was made out.

The repair of course was covered by warranty.

 

[Porpoise Hork]

This has been a thing in cars for the near 50 years I have been driving. The fuel gauge when working would remain on the full mark for seemingly impossible distances. Nearly every single car, truck, and even heavy machinery will do this. Most usually won't budge for 80-120 miles giving you the sense that it's got AMAZING economy until you reach 1/2 a tank. Then it's in a race to see how fast it can suck the tank down and turn on the low fuel light leaving you questioning your life choices and wondering just how much farther you can push it until it runs out and then you will have to literally push it... My 22 PB does this same thing and can regularly go around 100-120 miles before the gauge shows any consumption.

Now I just drive it about 300 miles or roughly 1/2 a tank and fill it back up and start this whole thing over again.

 

[Gros Ventre]

I am a proponent of checking plugs & connectors throughout the truck when a problem is found.

 

[wptorres]

I think where I'm confused as it seems to be very truck-dependant. My father's is almost completely accurate, only staying on "full" for a few gallons whereas mine doesn't seem to do the same. Is there any sort of adjustment I could make in the software? Or could the float in the tank be sticking?

 

[Kanuck]

The float is basically like a volume control, as it drops it changes resistance. Mass produced electrical component. They can't make them exactly the same. If you want to go down that rabbit hole, it's your choice. When mine gets to about half, I fill up. I don't look at how much it took, at half it should be this much product, it is what it is. But that is me.

 

[FirstFord]

I never actually take notice of the graphical fuel gauge, but instead the DTE value. In FORScan you can change the way DTE is calculated, but before mucking around with that (it's a decent algorithm already and shouldn't need changing) I would adjust AFE bias in Engineering mode to properly reflect real fuel economy instead of the reported which is always optimistic. This will affect the DTE value displayed and will make it more accurate.

Totally agree to all aspects of this. When I first picked up my truck from the dealer, the DTE was somewhere around the 750 mile mark. The first modification that I made to the truck was correcting the built-in MPG bias. The DTE has never been anywhere close to that since - but now, considerably more accurate!

The float is basically like a volume control, as it drops it changes resistance. Mass produced electrical component. They can't make them exactly the same.

Yep - Totally agree. The sending unit is a variable resistor, so arguably, it is an analog input to a digital gauge.

 

[PatchManager]

I have found my fuel gauge to be fairly accurate in everyway (MPG, level, and miles to empty).

 

[Gros Ventre]

Remember, the dash readout is what the computer wants you to know. In my case, with an auxiliary gas tank plumbed in, it refuses to acknowledge a rising level going down the road. Then when the level gets near full it will suddenly jump to an accurate level.

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