Hi, all,

I just took my first fairly lengthy highway trip at sea level with the CRD. Basically set the cruise control and went, going about 65mph. Over 320 miles, I averaged 28.2 MPG. Tires inflated to 36psi, cool and very humid. Engine only has about 1000 miles on it. When I first reset the computer at the start of the trip, I was going down a steep hill, and the mpg read 99.9 for awhile...that would be nice!

Anyway, what does the computer use to calculate MPG, and how accurate are you all finding it?

gr

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George Reiswig
2005 Jeep Liberty CRD
Suncoast, SEGR, lift, InMotion tune, homebrew B100
At 138k, new head & gasket, timing belt, rockers and swearing vocabulary

On another Chrysler product I had (2004 Dodge truck) I checked the overhead computer and I found it to be EXTREMELY ACCURATE. Kind of surprised me. But everytime I filled up my tank at the gas station I would hit the "reset" button on the mileage computer, and it would always be very very accurate at showing my average mileage.

The computer uses feedback from the engine, fuel injectors, etc. and does all sorts of complicated math to calculate the mileage. I don't know the specifics...I just know they work!

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2005 Stone White KJ Limited CRD 4x4
Off-Road Pkg
Trac-Lok
Emu 790s/948s
Skyjacker H7088s rear/Bilsteins front
15x7 Black Rock Lobos/31x10.50 Firestones
GDE HOT Tune + TCM Tune
Euro TC
CB radio
Thrush Turbo muffler
AEM DryFlow filter

I was curious as well as to the accuracy of my trip computer. I did several fill ups where I calculated it by hand and then compared it to the computer and soon realized that it was highly accurate.

Mine is pretty consistently high by about 2 MPG.

If only it was the real numbers.

My gage quite often still reads full 100 miles after I fill it up. Not sure if that has any effect or not.

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LOST Lifetime member #AJ051882
2005 Liberty CRD, 245X70X16 BFG AT's, 2.5 Daystar Spacer lift, Trac-Loc Diff, Skid plates

Mine is typically within .2 or .3 mpg of hand-calculations, provided it's filled up the same each time.
Greg

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2015 Jeep Grand Cherokee Limited 3.6L and A8
*SOLD*2005 Jeep Liberty Limited 4x4 CRD, Bright Silver Metallic, Dk/Lt Slate Gray Leather w/bun warmers, 5 spd auto, 22G pkg, Trailer Tow, 3.73 Rear Axle w/Trac-Lok Differential, P235/70R16 Firestone Destination LE's, Power Sunroof, Selec-Trac 4WD, Infinity 6-Disc In-Dash, Magnaflow #15870 System.