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-   -   EVIC MPG not accurate (http://www.jeepgarage.org/f107/evic-mpg-not-accurate-42348.html)

Boba10320 05-20-2012 10:14 AM

EVIC MPG not accurate
 
I have been comparing the MPG on the EVIC display to manually calculated MPG and they are off by quite a bit. The process that I have been using is this.

When I refuel, I reset the Fuel Economy on the EVIC and the mileage from the Trip Info. Next refill I write down the Fuel Economy from the EVIC and the mileage in the Trip Info. I then reset both again. I divide the mileage from the Trip Info by the gallons purchased from my fill up. I compare the MPG from the EVIC to the manually calculated MPG.

I have been doing this for 3 fill ups now. I have used 3 different gas stations just in case their pumps are not accurate. I figure not all 3 stations have pumps off in calibration. Although I guess anything is possible.

My results are that the EVIC MGP is .9 MPG higher than the manually calculated MPG for the 3 fill ups. All three fill ups were less than the EVIC number.

Has anyone else checked this? If so what did you find? Am I doing something wrong in my calculations? I have a 2012 Overland V6.

andyh 05-20-2012 10:34 AM

Re: EVIC MPG not accurate
 
.9 mpg = close enough

AAAA 05-20-2012 10:56 AM

Re: EVIC MPG not accurate
 
off by .9? Take it in to the dealer!!

2012 Summit 05-20-2012 11:23 AM

Re: EVIC MPG not accurate
 
This topic comes up often. Apparently some of us have dead-on results with the EVIC MPG (me included) and others see a variance. Fill-ups can vary depending on when the pump automatically stops and depending on how level the grade is at the pump.

Boba10320 05-20-2012 03:40 PM

Re: EVIC MPG not accurate
 
Quote:

Originally Posted by 2012 Summit (Post 632232)
This topic comes up often. Apparently some of us have dead-on results with the EVIC MPG (me included) and others see a variance. Fill-ups can vary depending on when the pump automatically stops and depending on how level the grade is at the pump.

I figured it might vary so I was hoping I would get a "bounce back" the other way on the MPG but so far that has not happened. I am always under the MPG from the EVIC.

2012 Summit 05-20-2012 04:00 PM

Re: EVIC MPG not accurate
 
Yeah, in your case it sounds like the EVIC MPG is inaccurate.

Shortdustoff 05-20-2012 04:46 PM

Re: EVIC MPG not accurate
 
Mine is usually 1mpg higher in the EVIC. Seems that all the mpg calculators I have had (Avalanche, Tahoe, suburban, Ram, Charger) all calculated about 1 mpg higher than I have actually calculated by hand. My guess is that it is a marketing strategy so when I see 25 mpg with a 3.6L I think yippee, must have had a tail wind. Then I calculate by hand and it is actually closer to 23.5. So now I choose to go along with wait the EVIC says, makes me happier that way.

Yadkin 05-20-2012 06:28 PM

Re: EVIC MPG not accurate
 
I don't think the EVIC calculates mpg as you'd think it would, total miles driven since rest divided by gallons consumed since rest. Apparently there is an algorithm that weights it towards your more recent miles.

josh3008 05-20-2012 07:19 PM

Re: EVIC MPG not accurate
 
Quote:

Originally Posted by 2012 Summit (Post 632232)
This topic comes up often. Apparently some of us have dead-on results with the EVIC MPG (me included) and others see a variance. Fill-ups can vary depending on when the pump automatically stops and depending on how level the grade is at the pump.

Like Summit said, If you only put 10 Gallons in at the next fillup then you will end up infront. unless you fill the tank to the exact level each and every time then your calcs won't be accurate.

Mongoose9400 05-20-2012 07:52 PM

You can't get an exact answer hand calculating if you don't know exactly how much fuel was used for the miles driven. You're guessing at how many gallons have been used. The Jeep EVIC knows how much it's used by injector flow rates and such.


Sent from my iPhone 4S

tnjeep 05-21-2012 06:03 AM

Re: EVIC MPG not accurate
 
My evic is usually about 1.3 mpg's towards the high end. I keep my mpg's on a spreadsheet (along with my other vehicles) and after 4 months and 5 thousand miles mine has settled right at 23.1 mpgs (80% highway). EVIC usually says 24.5 or so. Also, calculating by hand is much more accurate than what the computer is telling you! This is a big tank and even if the pump turns off a little faster than an the last gas station you used it still won't be off my more than a couple of tenths of a gallon on a 24.5 gallon tank.

ajs800 05-21-2012 08:20 AM

Re: EVIC MPG not accurate
 
MIne is usually dead on but it has been off a few tenths both ways when compared to hand calc.


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