Fuel gauge inaccuracy

[National Superbike]

I've noticed ever since I got this truck that the fuel gauge is pretty far off- like it says I am 25 miles to empty and I only put 19.5 gallons in it. I suspect this may also be why the MPG calculation is so far off too. The truck says 22.3 and hand calculated is is 20.6. At 20mpg, I should be able to drive almost another 100 miles before empty but the DTE would show 0 the whole time and the gauge would be sitting on empty. Anyone else notice theirs being off this much?

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[mkinttrim]

You can adjust how it reads the MPG. There are youtube videos on it, I believe you press the OK button (at least 5 seconds) while you turn on the truck BUT DONT START. A menu pops up on your drivers screen and you can scroll thru the different setttings

 

[Buyer2021]

perhaps of interest ....

Making the 'Lie-O-Meter' more 'honest' (Average Fuel Economy display) | F150gen14 -- 2021+ Ford F-150, Tremor, Raptor Forum (14th Gen) | News, Owners, Community, Discussions

 

[FirstFord]

Agreed. It seems that most (I'm tempted to say "all") of the factory MPG calculations are biased in favor of being overly optimistic. One of the very first changes I made to my truck was to correct the calculation to make it considerably more realistic/accurate.

I'll also note that my truck has a 3~4 gallon "reserve" that isn't recognized by the fuel gauge or in the DTE calculations, so the DTE doesn't factor in the truck having a reserve. This will be demonstrated, for example, when you fill up the tank when you are showing "DTE: 1", and you wind up putting in less fuel that what you may anticipate.

 

[National Superbike]

The mpg doesn't even bother me. I can calculate that in my head and I basically know it is off by 2mpg. The bigger problem is the gauge showing E and there still being 5 gallons in the tank- that's 19.2%. I get having a couple gallons left when it hits E so that people don't run out of gas, but not 5 gallons.

 

[Gros Ventre]

The fuel gauge shows you what the computer wants you to know. I installed an Auxiliary Gas Tank. It can pump into the main tank while on the road. It is clear that the computer doesn't believe it when fuel level rises going down the road. Only after extensive pumping does it finally pop up to a reasonable level.

 

[FirstFord]

The bigger problem is the gauge showing E and there still being 5 gallons in the tank- that's 19.2%. I get having a couple gallons left when it hits E so that people don't run out of gas, but not 5 gallons.

It sounds like we are on the same track.... Speaking for my truck (36 gal tank), I concluded the reserve of 3 to 4 gallons after noting DTE while hand calculating true MPG, over multiple tanks of gas. If I'm at 4 gallon reserve, and your estimate is 5 gallon reserve, it seems to me we're pretty close to the same thing....

EDIT: If you have the 23 gallon tank instead of the 36, then a 5 gallon reserve makes a sizable larger reserve, percentage wise, amplifying your concerns....

 

[Tall Tail]

Does the tank level and reserve account for slope, min pumping level, pump cooling, etc.?

Does the range use the avg mpg or avg trip mpg which would make the range non linear based on driving conditions?

 

[Risky Bizness]

Parts used to repair my fuel gauge problem are as follows:

LU5Z9276A (Gasket)
3U2Z14S411DGAC (Wire asy)
PL3Z9H307H (Sender and pump)

Other parts listed, but I don't know what they are, were:

2- 9002A6
2- 12650D
1- 1- 12650DX1
3- 12651D45
4- MT14S411


There were codes found, but are numerous. Main code was L69 (Concern Code), and code 42 Condition code.

Labor was $206.40

TOTAL was $633.26


Hopefully this is useful information for some one else.

"Risky Bizness"

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