E90Post
 


GetBMWParts
 
BMW 3-Series (E90 E92) Forum > BMW E90/E92/E93 3-series General Forums > General E90 Sedan / E91 Wagon / E92 Coupe / E93 Cabrio > Gas MPG Drop?



Reply
 
Thread Tools Search this Thread
      03-21-2018, 05:11 PM   #1
WhatDoIPutHere
Private First Class
WhatDoIPutHere's Avatar
13
Rep
193
Posts

Drives: 08 335i
Join Date: Oct 2017
Location: Los Angeles

iTrader: (1)

Gas MPG Drop?

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?
Appreciate 0
      03-21-2018, 05:30 PM   #2
jeddo45
Apprentice
United_States
254
Rep
666
Posts

Drives: 2007 BMW 335i
Join Date: Jul 2016
Location: LBC

iTrader: (0)

Quote:
Originally Posted by WhatDoIPutHere View Post
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.
Appreciate 2
      03-21-2018, 06:34 PM   #3
tcphoto
Lieutenant
238
Rep
587
Posts

Drives: E92 335i MT Coupe
Join Date: Dec 2009
Location: Madison, GA

iTrader: (0)

I find the sampling for MPG is relatively short, drive it for a few days and check it again.
__________________
Appreciate 1
      03-21-2018, 09:59 PM   #4
Eddien123
Lieutenant Colonel
United_States
679
Rep
1,869
Posts

Drives: E90
Join Date: May 2013
Location: New Jersey

iTrader: (0)

Quote:
Originally Posted by tcphoto View Post
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.
Appreciate 0
      03-21-2018, 10:01 PM   #5
labrador
Second Lieutenant
43
Rep
219
Posts

Drives: E90
Join Date: Mar 2018
Location: California

iTrader: (0)

The memory might have been cleared. So drive more and see.
Appreciate 0
      03-22-2018, 01:42 PM   #6
dsjr2006
Captain
United_States
137
Rep
792
Posts

Drives: '01 E39 540iA
Join Date: May 2013
Location: Metro Detroit

iTrader: (1)

Garage List
2010 BMW 335i  [0.00]
2001 BMW 540i  [0.00]
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.
__________________
E90 LCI N54 M-Sport : JB4 G5 - CP w/Tial BoV - 193M Wheels | E90 Technical Docs download: http://j.mp/bmwe90docs *good read, very detailed.
Appreciate 0
      04-17-2018, 11:11 PM   #7
WhatDoIPutHere
Private First Class
WhatDoIPutHere's Avatar
13
Rep
193
Posts

Drives: 08 335i
Join Date: Oct 2017
Location: Los Angeles

iTrader: (1)

Quote:
Originally Posted by tcphoto View Post
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.
Appreciate 0
      04-18-2018, 02:32 PM   #8
mecheng77
Lieutenant
mecheng77's Avatar
102
Rep
472
Posts

Drives: 2007 328i JBlk , Volvo S70 T5
Join Date: Nov 2017
Location: Ontario Canada

iTrader: (0)

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.
Appreciate 0
      04-18-2018, 02:56 PM   #9
avi312singh
Private
0
Rep
66
Posts

Drives: E90 LCI M Sport
Join Date: Apr 2017
Location: United Kingdom

iTrader: (0)

Quote:
Originally Posted by WhatDoIPutHere View Post
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...
Appreciate 0
      04-18-2018, 02:59 PM   #10
jt335i
Major
jt335i's Avatar
182
Rep
1,063
Posts

Drives: 2010 E92 335i Monaco blue
Join Date: Jan 2010
Location: Tampa, Fl

iTrader: (0)

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.
__________________
2010 BMW 335i: Monaco blue metallic/Premium+Sport Auto-Steptronic, BMW PE, Cobb Stage 2
2005 Mustang GT: Redfire metallic/5-spd/Ford Racing (Axle backs, silver Bullitt wheels)/K&N CAI/ Diablo Sport Predator Tuner
1997 Toyota Corolla
1983 Mercedes Benz 380SL Roadster
Appreciate 0
Reply

Bookmarks

Tags
335i, battery, mpg, n54

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 05:18 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST