[WhatDoIPutHere]

I just recently had to disconnect the battery from the car and after I put everything back together I noticed the MPG on the cluster dropped. It used to be around 19mpg, but it is now 13.5. It just adjusted itself to 14, but this seems insanely low. All I did was take off the negative from the battery. Any reason for the sudden change in mpg?

[jeddo45]

Originally Posted by WhatDoIPutHere

I just recently had to disconnect the battery from the car and after I put everything back together I noticed the MPG on the cluster dropped. It used to be around 19mpg, but it is now 13.5. It just adjusted itself to 14, but this seems insanely low. All I did was take off the negative from the battery. Any reason for the sudden change in mpg?

Everytime I use Carly to recode anything on my instrument cluster, the car reads 120 degrees Fahrenheit outside. Obviously that's wrong and it eventually resets itself.

Drive the car man. Guarantee you nothing has changed and it will reset itself to the proper reading.

[tcphoto]

I find the sampling for MPG is relatively short, drive it for a few days and check it again.

[Eddien123]

Originally Posted by tcphoto

I find the sampling for MPG is relatively short, drive it for a few days and check it again.

Agreed. My range will drop by like 45 miles after one pull but it'll go up 45 if I sit 50mph for a few minutes. My mpg once read 99.9. I didn't reset it or anything it was like months in the making for my average and it eventually worked it's way down to like 26 where it's stayed.

[labrador]

The memory might have been cleared. So drive more and see.

[dsjr2006]

I assume the 19 MPG average was with lots of driving at a steady speed like highways and such. The 13 MPG is about what I would see just stop and go in the city, especially taking off kinda quick. It'll average back out with time. If I reset mine on the highway it will show like 25-28 MPG, but quickly got back down to around 20 MPG once I'm back driving in the city.

[WhatDoIPutHere]

Originally Posted by tcphoto

I find the sampling for MPG is relatively short, drive it for a few days and check it again.

I know this is a late response, but you were right! MPG reading came back to 17.5. Used to be 19, but I don't know how accurate that is. I drive on an open road in the morning, but some traffic (sometimes major stop and go) in the evening time, so I take it that's why the mpg reading keeps changing.

[mecheng77]

I think after a hard reset, the fuel maps gets reset so it takes some time for proper feedback from MAF and O2 sensor to get the mpg to improve.

[avi312singh]

Originally Posted by WhatDoIPutHere

Any reason for the sudden change in mpg?

I am pretty sure you can code the KOMBI module to have a real time MPG reading?? Not sure though definitely know you can do velocity as I have..

Try resetting the reading using the stalk in the OBC and drive it around for few dozen miles or so...

[jt335i]

That's the average consumption that the car's computer keeps a running calculation.
If you manually reset it, or disconnect the battery as you mentioned, then it will restart at zero and start a new running calculation until you reset it again.