Gas mileage on display

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Russ01

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Hi, I have a 2019 Ram 1500 laramie longhorn. After every fill up, with the truck sitting still, the gas mileage shows I am getting 4.7 mpg. But, I am not moving at all. Shouldn't this read 0 mpg?
 

Kickboxer

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The mileage readout is hard to understand. So don't read much into that reading.
Just use it as a long term mileage suggestion, that means over hundreds or thousands of miles. Then it may be a more useful thing.
The best way to track mileage of course, is to keep a log, notebook with a
odometer reading, miles traveled and gallons filled.
 

ColesRAM

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I’m bumping this post because I’m also interested in the accuracy of the ECO system readouts. I’ve started a log (I’ve had my 2020 RAM for about a month now) to track my mileage but would appreciate a guess as to what I can expect. On a recent drive south on US17 to the mountains of Palatka here in the NE corner of FL, we were indicating up to 27.4 mpg! My lovely wife was thrilled, I was skeptical. So, what is more realistic? Thanks all.
 

Dean2

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The EVIC on my 2021 2500 6.4L is within .3 of my hand calculated log over 11,800 klms. I leave trip B to accumulate all mileage to date, and reset trip A at every fill. On a per trip basis the amount Trip A it is out is larger, from .7 over to 1.3 mpg under.

Recently posted this on an other thread.

Small update. At 11,000 Klms I have recorded every tank of gas that has gone into my 2021 Laramie Crew Cab Long Box, 2500 with 3.73 gears. Almost all of the miles are on 87 Octane gas which has about 10% ethanol in it. The higher octane did not give enough better mileage to warrant the extra cost.

My all in, hand calculated average is 15.4 mpg. Lowest full tank was 10.3 mpg, highest was 18.9. I did hit an EVIC, which reads within .1 to .4 of hand calculated most of the time, rated 22.2 mpg for a 500 KLM stretch on part of one tank, but the rest of the way was into a huge headwind and dropped the overall average for the full tank fill. Mileage is about 50% highway rest, hunting and around town. This is a significant improvement from my V10.
 

zogg

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The mpg display is usually close to accurate as it is on any vehicle. The only way to get a true picture is to hand calculate every tank of gas.

I used to drive myself crazy over mpg numbers. I finally realized that the only display that matters is the fuel gauge. When it get low, I fill up. I’ve learned that mpg numbers don’t matter…if I need gas I buy it. Whether I get 15 mpg or 25 mpg, I still need fuel when the gas gauge goes towards the big “E”.
 

Dean2

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The reason to keep a detailed log book are far more numerous than just tracking gas mileage. That is one thing you get, but it also gives you a record of maintenance intervals and cost, repairs etc are all recorded. Also, modern computers are so adept that a least a few times, a large drop in gas mileage was the first time I became aware there was an issue with one of our trucks.

The log book information is usefiul on its own, especially to those buying the vehicle used, but also critical if you are writing off your vehicle epxenses on income tax.
 

Irishthreeper

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For OP…sitting still at idle will quickly cut down your MPG readout. It’s misleading on your over-all mileage but I guess it’s figuring gas is being used but no miles covered.
 

ColesRAM

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So, to confirm, the ECO mpg calculation is relatively accurate to within say 10% or so?
 

Dean2

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So, to confirm, the ECO mpg calculation is relatively accurate to within say 10% or so?
Need to retake your math class. :) Mine is accurate to within 2 or 3% most of the time. 10% on 15 mpg would put you out 1.5
 

ColesRAM

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Need to retake your math class. :) Mine is accurate to within 2 or 3% most of the time. 10% on 15 mpg would put you out 1.5
That’s what I wanted to know. I was being generous with the 10% tolerance. So your experience is 2-3%. It’s that accurate. Neat! So the 27+ mpg that I was getting on our short trip was amazing. Great…..
 

zogg

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I might suggest that if you’re reading 4.7 mpg when stopped that the 27 mpg may possibly be 4-5 mpg too high. Actually that would make sense because I never owned a truck that got 27 mpg…even an older diesel or a mini truck with a four cylinder
 

JayLeonard

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I might suggest that if you’re reading 4.7 mpg when stopped that the 27 mpg may possibly be 4-5 mpg too high. Actually that would make sense because I never owned a truck that got 27 mpg…even an older diesel or a mini truck with a four cylinder
I approached that when I had my old 91 D250/Cummins with the 5 speed manual. I could get 25 if I tickled the go pedal or 24 if I hammered it.
I miss that beast!!
When I do my calculations with my 2021 2500 I get about 3 mpg less than the lie o meter indicates. It will say 18 and I’ll calculate 15.
 

ColesRAM

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I might suggest that if you’re reading 4.7 mpg when stopped that the 27 mpg may possibly be 4-5 mpg too high. Actually that would make sense because I never owned a truck that got 27 mpg…even an older diesel or a mini truck with a four cylinder
I’m not the OP and hadn't noticed that particular problem with my truck. I did notice, as I posted earlier, that on a short hi way trip on flat open road using CC, we were indicating 27+ mpg, which I thought was suspect. Just wanted to hear what others were thinking about the systems accuracy.
 

Timsdually

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Hi, I have a 2019 Ram 1500 laramie longhorn. After every fill up, with the truck sitting still, the gas mileage shows I am getting 4.7 mpg. But, I am not moving at all. Shouldn't this read 0 mpg?
Is that the display showing or is it the trip meter telling you that.
trip meter gives your average from the last time you reset it.
The display image tells you what is happening at the moment.
 

Dean2

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Here is the read out in my 2500, sitting still, after travelling 300+ klms. Notice the zero, upper right centre with the yellow dot I put beside it.20220816_160327.jpg
 
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