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Parks311 10-03-2011 09:53 AM

EVIC Gas Mileage Accuracy
I was looking through the threads and couldn't find what i was looking for so I apologize if it is already out there in advance.

Regarding the EVIC gas mileage display, it does not seem to be very accurate. I would say mine is consistently showing 1.5-2 mpg better than what I calculate out from fill-up to fill-up. My EVIC shows around 19.6-20.4 mpg and I only calculate out to around 17.8-18.5. My gas mileage also seems to be higher for the first quarter of a tank, drop-off for about a half of a tank and then slowly climb again for the last quarter of a tank. My driving is pretty consistent with mix of high way and city driving and the same route everyday. Seems like a software thing to me because it will also sometimes default to the TPMS display when I hit the back button from the fuel economy screen rather than the main menu.

Has anyone else noticed this big of a discrepancy? Is this a computer glitch or to the 20 inch wheels play into accurate calculations as well?

robpp 10-03-2011 10:19 AM

Re: EVIC Gas Mileage Accuracy
common with wk1......i would assume it continues.

if you want to calculate gas mileage get gas buddy or an app or a pen and paper/ ditch the evic for any accuracy.

pwguy 10-03-2011 10:19 AM

Re: EVIC Gas Mileage Accuracy
My V6 Laredo X has about 11,000 miles on it. The EVIC gas mileage display has been pretty consistently optimistic by 1 1/2 to 2 mpg, similar to yours. For instance it will show 22 mpg at a fill-up but the actual gas mileage will calculate out to 20.5 mph.

One time the display average jumped way up suddenly and the discrepancy was much larger for that fill-up.

For the last two fill-ups the display has been pretty much dead nuts on (within .1 mpg of what was calculated). I hope that is a new trend.

I suspect most of the reported mpg figures on this board are from the display, so I sort of automatically discount them.

Archer9 10-03-2011 10:28 AM

Re: EVIC Gas Mileage Accuracy
I find the EVIC can be very accurate. On the other hand I also find it can be fooled. I would never trust the EVIC mileage figure number to be absolutely correct. Pencil and paper or spreadsheet is the only way to be sure of your gas consumption.

felipito 10-03-2011 11:16 AM

Re: EVIC Gas Mileage Accuracy
what if the EVIC is right and the gas station is programmed smaller gallon in their computer and the fills up your jeep and charges normal gallons. this way you will have less gas for more money.
Example: Gas station Computer has a gallon in 0.95% of a gallon and charges you for the entire gallon, this multiplied by 20 gallons are 1 gallons which is charged but not inserted in your tank. this could mess up your hand and paper calculations and the cars computer could be right.
in my country this could be the case...i dont know if in US this happens.

Archer9 10-03-2011 11:43 AM

Re: EVIC Gas Mileage Accuracy
That thought has crossed my mind, too. I have seen some gas pumps that I didn't trust. Even if the gallons are accurate I wonder if sometimes you're paying for the gas that's remaining in the hose (and that you didn't get).

ColdCase 10-03-2011 11:47 AM

Re: EVIC Gas Mileage Accuracy
There is a recent TSB out that addresses EVIC mileage accuracy.

andyh 10-03-2011 01:05 PM

Re: EVIC Gas Mileage Accuracy
My EVIC is money. Never more than a couple tenths off.

77Cherokee 10-03-2011 06:13 PM

Re: EVIC Gas Mileage Accuracy

Originally Posted by felipito (Post 493468)
i dont know if in US this happens.

Around here the pumps are checked for accuracy on a regular basis by the government's Division of Weights and Measures.

Jeff_Jeske 10-03-2011 07:16 PM

Re: EVIC Gas Mileage Accuracy
I just took a 3400 mile road trip out east. I manually calculated mileage and compared it to the EVIC. The EVIC was dead on the nuts. FWIW I managed 20.1 MPG at 75mph for the first half of the trip. During my return trip I was cruising around 85-90 and put the hammer down several times leaving toll booths and merging... as result I only pulled 17.4 on the way back.

Kev- 10-03-2011 08:03 PM

Re: EVIC Gas Mileage Accuracy
Another thing everybody should realize when calculating mileage: Your odometer is not 100% accurate, either.

Use a GPS based odometer if you want really accurate MPG calculations.

Lingohocken 10-03-2011 08:10 PM

Re: EVIC Gas Mileage Accuracy
Don't forget to adjust for ethanol content, which drops mileage. Wastes perfectly good corn, too!

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