Gas Gauge/Low Fuel Light/Range Estimation Question

I've had my GCL for 3 weeks now and have put close to 2,000 miles on it so far. Everything is great with the vehicle but I am puzzled by the gas gauge and range estimation.
1) The gas gauge stays above half for most of the tank despite having used over half of the fuel, and then when it gets below a 1/4 it doesn't seem to match up at all with what is left in the tank.

2) The range estimator tells me fairly consistently that I should be getting something close to 500 miles out of each tank, but I've yet to break 400.

3) With my first tank I got no less than 5 texts from the car telling me that I was low on gas and suggesting I get gas. With the 2nd tank my low fuel light came on (no texts) and I am embarrassed to say that I actually ran out of gas (first time in my life doing that) because I drove 7 miles total between the light coming on and the car stalling. WIth my previous car I had a range of at least 50 miles from when the low fuel light would come on. Since running out of gas I have become keenly observant of the gas gauge and have been trying to figure out what is going on. It seems with such a sophisticated vehicle that having an accurate gauge and range to empty would be a no brainer (and that it should appear on the home screen of the dashboard).

Is anyone else seeing this stuff happen with their vehicles?

I have noticed that I have VERY LITTLE RANGE (10-15 miles max) once the fuel light comes on (haven't run it dry though). It seems like that last number I see for remaining range is '50 miles', and then the fuel light comes on. I almost ran out of gas twice on my 'delivery drive' home from AR to WY; both times filling within 10-15 miles of the light coming on, and able to put 24 gallons in without trying to squeeze in a full 'topping off').

When that fuel light comes on, you better get gas NOW. It also says the tank has a 22.98 gallon capacity, but I have put up to 25.354 gallons in it (topping it off, fuel almost coming out), and that was within a couple miles of the fuel warning light coming on. I don't know what to think. Worst of all, my V8 is averaging 13 miles per gallon in mixed driving (ugh), which is a meager 325 miles of range at 25 gallons, or 300 at the rated 23 gallons. May as well have bought an older Trackhawk and had all that power!

Interesting. I too have been scratching my head filling up because I'll get down to a quarter of a tank on the gauge and have put 20 gallons in. I'm not great at math, but if it has a 23 gallon tank I shouldn't be able to put that much in. I have the v6 and am getting a bit over 17 mph so far with a mix of city and highway.

We are getting 19 mpg average and most of our driving is highway in the rural areas of flat Illinois. I see another class action lawsuit coming over EPA fuel estimates. It seems like they lied and it’s not gonna get what they claimed. Our previous vehicle was a 2020 explorer and that one always got one or two mpg over what they claimed on the windows sticker.

Def notice the gauge will stay at the full capacity for a while before starts to show reduction digitally. Little weird suppose ya jus never thought much of it. Also averaging 16-18 mpg 4x2 hwy driving w a bit of a heavy foot in hilly Austin. I'm guessing has something to do with the float valve sensor thing thing detects liquid levels in a big wide fuel tank where capacity would seem to get low relatively quick for floating device. Otherwise love the exceptional total fuel capacity as have noted.

Bradef said:

Def notice the gauge will stay at the full capacity for a while before starts to show reduction digitally. Little weird suppose ya jus never thought much of it. Also averaging 16-18 mpg 4x2 hwy driving w a bit of a heavy foot in hilly Austin. I'm guessing has something to do with the float valve sensor thing thing detects liquid levels in a big wide fuel tank where capacity would seem to get low relatively quick for floating device. Otherwise love the exceptional total fuel capacity as have noted.

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Makes one wonder if it’s not a calibration issue between the sending unit in the tank and computer that controls the dash. When the low fuel light comes on the vehicle should have about 50 miles left to empty. Which should be approximately 2.5 gallons or so. Luckily my wife is pretty good about filling up before the 1/4 tank. I on the other hand have a bad habit of seeing how far I can push it. I will not be pushing my luck in the jeep that’s for sure. Lol

I wish I knew what the actual total capacity of the tank was, but it does seem like you should have about 2 gallons left when the light comes on. I got over 25 gallons into a 23 gallon tank within a couple miles of the light turning on, so it would sure be nice if it could be calibrated differently.

We have noticed this too with our Jeep. I’ve had several instances where I’ll be filled up completely full. We’ll drive a fair distance and the miles to empty has increased instead of decreased! We also found out not to trust the low fuel light when it comes on. Like others have said, normally you have roughly 50 miles left when the light comes on. For the first time, I was worried I was going to run out of gas because of how inaccurate the gauge, the low fuel light, and miles to empty is on the vehicle. We now know not to push our luck when it comes to making sure it’s filled up.

This is the first vehicle I’ve owned where “E” actually means empty. All my other vehicles at “E” meant there were still about 2 gallons

The manual states that the light will go on when approximately two gallons are left in the tank. Mine went on shortly after I showed about 40 miles range left. At the time, my average was about 19.5 mpg. So, it appears that things are accurate.

I've never seen less than 50-60 miles range for a projection, then it just goes to 'low fuel'. My other cars (IE BMW) will show remaining range down to about 10 miles before going to '0', which is a LOT more helpful when you get tot that point.

Have you seen whether it says what the total tank capacity is, i.e. 'reserve' plus normal capacity? How are they publishing that it's a 23 gallon tank and I'm putting in 25.3 gallons within a couple miles of the 'low reserve' light coming on??? Seems like that should mean it holds 27 gallons, but that can't be possible? Or is it?

I am getting 13.5mpg in my V8 (I've only done short 5mile trips for the past month+), so 2 gallons = 27miles at best. But given the hills here in East TN, I'd say it's likely to end up being only 10 miles + the distance to the next hill.

Either way, my general rule with all vehicles has always been that when my tanks hit 1/2, I'll fill up at the next top tier station I see that lets me make a right hand turn out of it when I go to leave. If I'm doing a long distance drive on the interstate, I'll start choosing my station to stop at when the tank shows 1/2 with a general requirement to be filling up sometime before I get to 1/4 tank.

GoVols said:

I am getting 13.5mpg in my V8 (I've only done short 5mile trips for the past month+), so 2 gallons = 27miles at best. But given the hills here in East TN, I'd say it's likely to end up being only 10 miles + the distance to the next hill.

Either way, my general rule with all vehicles has always been that when my tanks hit 1/2, I'll fill up at the next top tier station I see that lets me make a right hand turn out of it when I go to leave. If I'm doing a long distance drive on the interstate, I'll start choosing my station to stop at when the tank shows 1/2 with a general requirement to be filling up sometime before I get to 1/4 tank.

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Yeah, it's just weird that it says '50 miles' for range, and then the fuel light comes on and a couple miles later you can put over 25 gallons in it.

OK.. from a 60 year old who's been through this with other FCA vehicles: The remaining gas mileage seen on your dash is directly proportional to the gas mile age your getting at the exact time your driving. if you nurse the throttle, the fuel mileage goes up - if you don't - it comes down. Also, the gas tank is a little larger than the posted specification by FCA. The slower you pump the gas, the less air you have in the tank and the more you can get in the tank. The faster - more air, likewise, less gas. Saying this - not all gas station have the same pumps. Some pump faster than others. If I have to go on a long trip, I pump the gas very slow, then I know I've literally tipped it off and can go as far as the tank and my driving habits will take me. Hope this helps.

That still doesn't explain why mine says I have 50 miles remaining, and then within the course of 2-3 miles it switches to 'low fuel' from 50 miles remaining, and then I can put 25.3 gallons in a 23 gallon tank. It may seem like splitting hairs, but when your reserve light goes on, hairs are all you have.

Sarge said:

That still doesn't explain why mine says I have 50 miles remaining, and then within the course of 2-3 miles it switches to 'low fuel' from 50 miles remaining, and then I can put 25.3 gallons in a 23 gallon tank. It may seem like splitting hairs, but when your reserve light goes on, hairs are all you have.

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Yeah sounds like a calibration issue with yours sarge. Like maybe the sensor is hanging up and then all of a sudden dropping.

Deere78 said:

Yeah sounds like a calibration issue with yours sarge. Like maybe the sensor is hanging up and then all of a sudden dropping.

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That's what I think. If nothing else, I'd like to have it calibrated to leave me 3-4 gallons and err on the conservative side.

The manual states the capacity is “approximately” 23 gallons. Engineer speak for who knows. I have noticed the top half of the tank last forever and bottom half goes quick. I assume this is due to an oddly shaped tank. Most level gauges are calibrated for fuel height not volume. A curve has to be developed to correlate the height to volume. In oddly shaped tank this curve requires polynomial curve fitting, meaning it changes as the level goes down and is not linear. Imagine an upside down pyramid as a worst case. I doubt Jeeps lazy software engineers took this into consideration. After all, consider these software geniuses that have screwed us all at this point with the issues. I have a personal 1/4 tank rule, I never go below this. The fuel pump requires cooling and it comes from the fuel. IMO it is terrible practice to go below 1/4. I live in Ohio where it freezes. Any water in the fuel lays at the bottom. If the tank is empty it would freeze faster due to low mass of fuel/large air space in tank.

The manual also states that 89 octane is recommended for optimum power AND mileage. I have tested this on a different vehicle years ago and 89 was better MPG and $ per mile than 87. 93 was no better than 89. Obviously this was not a GCL or GC. This is engine dependent due to its design. These are not urban myths, there are real studies to confirm this.

Take your mpgs now. Stop buying 87. Run a full tank of 89 and see. If manual states 89 is recommended, I am sure EPA estimates are using 89 or better.

In addition, 89 can help with carbon buildup due to burning slower and creating higher combustion/exhaust gas temps. This is very important for GDI engines (which the GCL is not) and also catalytic converters.

eleceng1979 said:

The manual states the capacity is “approximately” 23 gallons. Engineer speak for who knows.

The manual also states that 89 octane is recommended for optimum power AND mileage. I have tested this on a different vehicle years ago and 89 was better MPG and $ per mile than 87. 93 was no better than 89. Obviously this was not a GCL or GC. This is engine dependent due to its design. These are not urban myths, there are real studies to confirm this.

Take your mpgs now. Stop buying 87. Run a full tank of 89 and see. If manual states 89 is recommended, I am sure EPA estimates are using 89 or better.

In addition, 89 can help with carbon buildup due to burning slower and creating higher combustion/exhaust gas temps. This is very important for GDI engines (which the GCL is not) and also catalytic converters.

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Manual only states this for the V8. V6 it recommends 87 and explicitly states no benefit for running anything higher.

eleceng1979 said:

The manual states the capacity is “approximately” 23 gallons. Engineer speak for who knows.

The manual also states that 89 octane is recommended for optimum power AND mileage. I have tested this on a different vehicle years ago and 89 was better MPG and $ per mile than 87. 93 was no better than 89. Obviously this was not a GCL or GC. This is engine dependent due to its design. These are not urban myths, there are real studies to confirm this.

Take your mpgs now. Stop buying 87. Run a full tank of 89 and see. If manual states 89 is recommended, I am sure EPA estimates are using 89 or better.

In addition, 89 can help with carbon buildup due to burning slower and creating higher combustion/exhaust gas temps. This is very important for GDI engines (which the GCL is not) and also catalytic converters.

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The v6 states 87 octane and the mileage isn’t meeting the advertised mpg either.