E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > E46 Xi Forum

E46 Xi Forum
The E46 XI was produced from 01-05 in sedan and touring body styles. Powered by either a 2.5L inline 6 in the 325xi or a 3.0L inline 6 330xi. Discuss all thing about BMW AWD E46 'Xi' here.

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 01-06-2010, 11:23 AM   #1
small_m
Registered User
 
Join Date: Sep 2009
Location: detroit
Posts: 33
My Ride: 2002 325xit
Question Bad MPG in my XI... is this normal

I seem to be filling my car up all the time! I drive a 2002 xit manual. I dont have the trip computer but i have calculated that i am getting roughly 19-20mpg. This seems quite low concidering that i spent most of my time on the freeway. I would like to know what other xi drivers are getting. I dont drive with my foot on the floor the whole time so I am wondering if there could be something wrong with my car. I hear that a bad vanos can cause poor gas milege. Any other suggestions if looks like my car is drinking more than it should
small_m is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 01-06-2010, 11:46 AM   #2
Kubica
Registered User
 
Join Date: Apr 2008
Location: Boston
Posts: 4,384
My Ride: 2003 325xi
I'm sure your vanos is fine.

Do you have any codes? I would start there- get them read.

I would replace the fuel and air filters, make sure you have good oil, check your tire pressures, check your intake for any cracks or leaks, spark plugs, and make sure you don't have a sticking caliper, etc.
Kubica is offline   Reply With Quote
Old 01-06-2010, 11:53 AM   #3
Chibo
Registered User
 
Join Date: Jul 2004
Location: Not Here
Posts: 275
My Ride: Nothing
I'm also getting right around 20mpg, I think it's normal, but I also waste gas sometimes.
__________________
1991 BMW 318iS - Alpine White - 5spd - GC Coilovers and stuff
2001 BMW 325xi - Alpine White - 5spd - H&R Coilovers, Catback, Sharked, Azenis RT615s, etc.
2000 Yamaha R1
2006 Suzuki GSXR750
Chibo is offline   Reply With Quote
Old 01-06-2010, 11:59 AM   #4
wdeerfield
Registered User
 
wdeerfield's Avatar
 
Join Date: Jan 2008
Location: Clifton Park, New York
Posts: 3,523
My Ride: 2009 E90, 2011 F10
i drive highway and get approx 25-28 mpg.

but also, remember that during the winter, gas quality is poorer..

i would change your spark plugs, fuel filter, air filter, oil and filter as others have mentioned.
__________________

2009 MBM E90 | ZPP | ZSP | ZCW | CA | 6FL | NAV | XENONS | 18x8.5 VB3s ET30/25
2011 JB F10 | ZPP | ZSP | ZCW | 6FL | NAV | 331s Square
wdeerfield is offline   Reply With Quote
Old 01-06-2010, 12:03 PM   #5
GuidoPorkchop
Registered User
 
Join Date: Aug 2009
Location: Somerset, NJ
Posts: 164
My Ride: 2003 325xi
Ditto...I have 98k on my bad boy...I'm hoping the new plugs and air filter helps out a bit. Does anyone know what the most gas efficient speed is for the xi? 55MPH?
GuidoPorkchop is offline   Reply With Quote
Old 01-06-2010, 12:24 PM   #6
CRXnut
Registered User
 
Join Date: Dec 2008
Location: Vancouver
Posts: 504
My Ride: 2004 325ci
what's your tire pressure?
CRXnut is offline   Reply With Quote
Old 01-06-2010, 12:27 PM   #7
GCoop
Registered User
 
Join Date: Jan 2009
Location: Charlottesville VA
Posts: 1,077
My Ride: '04 325xi
Highway only -- In the High 20's.
  • All time high was 31.5 (OBC) on a 280 mile trip returning from PA to VA
Mixed -- Mid 20's

Town only -- Low 20's
GCoop is offline   Reply With Quote
Old 01-06-2010, 12:29 PM   #8
wdeerfield
Registered User
 
wdeerfield's Avatar
 
Join Date: Jan 2008
Location: Clifton Park, New York
Posts: 3,523
My Ride: 2009 E90, 2011 F10
Quote:
Originally Posted by GuidoPorkchop View Post
Ditto...I have 98k on my bad boy...I'm hoping the new plugs and air filter helps out a bit. Does anyone know what the most gas efficient speed is for the xi? 55MPH?
i find keeping it under 2500 rpms is the sweet spot, easy on the accelerator and limit your braking, utilize coasting into off ramps as oppose to gas pedal and then braking late.. I do cruise control at 68-71 and get good results.
__________________

2009 MBM E90 | ZPP | ZSP | ZCW | CA | 6FL | NAV | XENONS | 18x8.5 VB3s ET30/25
2011 JB F10 | ZPP | ZSP | ZCW | 6FL | NAV | 331s Square
wdeerfield is offline   Reply With Quote
Old 01-06-2010, 12:48 PM   #9
Mark M
Registered User
 
Join Date: Sep 2009
Location: Lancaster, PA
Posts: 420
My Ride: e30 M3 / e90 335d
I do ~70 miles a day which is about 50% highway at 80mph, 50% rural roads at 50mph.

If I am light on the pedal I can average ~27mpg per tank. If I am enthusiastic I typically score about 22mpg per tank per the OBC.

Make sure your tires are properly inflated.
__________________
Mark M is offline   Reply With Quote
Old 01-06-2010, 01:43 PM   #10
Kubica
Registered User
 
Join Date: Apr 2008
Location: Boston
Posts: 4,384
My Ride: 2003 325xi
Yeah, i get 24.5 mpg on summer tires and 26.5 on all-season tires.

OP- this is what i would do:

1) check tire pressures first- i like 33Front/36rear
2) Fill up with Shell v-power
3) get a new Mann air filter
4) Check plastic intake prices for leaks

5) Drive half a tank and see if mileage goes up (forget the on-board computer, use the trip mileage counter and divide by gallons)

6) If that doesn't help, replace spark plugs (easy- NGK BRK EQUP) and fuel filter (messy- Mann).

Do you have any other symptoms besides low mpgs? No vibrations, rattles, noises, feelings that seem odd?
Kubica is offline   Reply With Quote
Old 01-06-2010, 07:44 PM   #11
dpgrand
Registered User
 
Join Date: Nov 2006
Location: Somerville, MA
Posts: 1,285
My Ride: 2005 330xi
I average about 22 and i have the Dinan stage 3 throttle body
__________________
'05 330xi - Koni, H&R, Rogue, Supersprint, UUC, Dinan, Apex
dpgrand is online now   Reply With Quote
Old 01-06-2010, 08:00 PM   #12
Vade46!!!
Registered User
 
Join Date: Jan 2009
Location: Long Island, N.Y.
Posts: 48
My Ride: '03 AW 325xi
During the summer I was averaging near 24mpg and now getting just under 23mpg in below freezing temps. I drive about 50-75 miles a day, mostly highway, and I'm usually beating the crap outta the car. Since I have an automatic, I'd assume that what your getting with a manual is well below where it should be.
__________________
'03 Alpine White BMW 325xi
'13 Victory Red Cruze LTZ
'12 Victory Red Silverado 1500 LT

'07 Victory Red Corvette Z51 3LT
Vade46!!! is offline   Reply With Quote
Old 01-06-2010, 08:04 PM   #13
Dreamliner330
Registered User
 
Join Date: Jun 2008
Location: Minnesota
Posts: 2,849
My Ride: 330xi
I average 22/23...330xi/5spd.
Dreamliner330 is online now   Reply With Quote
Old 01-10-2010, 01:22 PM   #14
small_m
Registered User
 
Join Date: Sep 2009
Location: detroit
Posts: 33
My Ride: 2002 325xit
Good to hear i am about normal then. I do drive rather enthusiastic too which doesnt help. I have done all that is suggested bar the fuel filter.
Thanks for all the feedback
Lee
small_m is offline   Reply With Quote
Old 03-20-2010, 10:45 PM   #15
chandrab
Registered User
 
Join Date: Jan 2010
Location: Boston, MA
Posts: 5
My Ride: Lotus Esprit SE/BMW?
I'm getting 19.9 on my 325xi, which surprised me considering it a 70/30 split of highway/city and I don't have a lead foot. I just replaced my sparkplugs and air filter today...I'll report back if I see an increase. I was surprised that I had OEM Bosch +4 installed and at 82K miles they looked pretty worn.

-Chandra
03 325xi
91 Lotus Esprit SE
chandrab is offline   Reply With Quote
Old 12-14-2010, 09:05 PM   #16
gordo325xiwagon
Registered User
 
Join Date: Apr 2005
Location: Daytona Beach FL
Posts: 104
My Ride: '01 325xit Step
A little controversy to stir the pot.

All the suggestions for better mileage are good, except the one about changing air filters. Unless an insufficient amount of air is getting through [sic. a completely clogged filter], a dirty air filter will NOT decrease your car's mileage; and changing it out will not increase your mileage.

I know this seems to run against everything we were taught about internal combustion engines; but all these recommendations advising a filter change refer to cars with carburetors, not electronic fuel injection (EFI).

Cars with EFI and Mass Air Flow meters always adjust the air/fuel ratio mix. If the throttle plate is opened, more fuel is allocated. The throttle plate is a much greater restriction to air flow, than any dirty filter could become.

Consequently, at a given speed, the throttle plate may be open wider on a car with a dirty filter; the amount of air is always the same. Hence no advantage to having a clean filter to allow more air... you don't need more air.

The only exception to this dynamic is at WOT wherein the total amount of air available has been diminished. In this case the power of the engine is likewise compromised. But in everyday driving, the air fuel mix always remains the same, regardless of dirty or clean air filter,... and so does the mileage.
__________________
____________________________________________________________ _____________


1993 300 ZX Twin Turbo (360hp @16psi) // 1997 Jag XK8 Luxor Cruiser // 2001 325xit Best Blend of Ride and Handling
gordo325xiwagon is offline   Reply With Quote
Old 12-15-2010, 02:48 PM   #17
TwoDuckDad
Registered User
 
Join Date: May 2010
Location: Portland, OR
Posts: 275
My Ride: 2001 330xi jet black
pure interstate driving with some hills over a 260 trip I make twice a week using premium branded gas, car running like a champ, only engine mod is Dinan cold air intake and Dinan stage II software and I get 27mpg going 75-80mph and light on the pedal and 225/45-17 tires on stock wheels at 35psi with only me and light luggage in car. I don't spend enough time driving in the city to give any figures.
__________________
Premium, Sport, & Cold Weather Packages
If you dog doesn't like somebody maybe you shouldn't either.
TwoDuckDad is offline   Reply With Quote
Old 12-15-2010, 03:00 PM   #18
SamDoe1
Registered User
 
Join Date: Oct 2010
Location: Minnesnowta
Posts: 3,486
My Ride: Clubs baby seals
Quote:
Originally Posted by gordo325xiwagon View Post
All the suggestions for better mileage are good, except the one about changing air filters. Unless an insufficient amount of air is getting through [sic. a completely clogged filter], a dirty air filter will NOT decrease your car's mileage; and changing it out will not increase your mileage.

I know this seems to run against everything we were taught about internal combustion engines; but all these recommendations advising a filter change refer to cars with carburetors, not electronic fuel injection (EFI).

Cars with EFI and Mass Air Flow meters always adjust the air/fuel ratio mix. If the throttle plate is opened, more fuel is allocated. The throttle plate is a much greater restriction to air flow, than any dirty filter could become.

Consequently, at a given speed, the throttle plate may be open wider on a car with a dirty filter; the amount of air is always the same. Hence no advantage to having a clean filter to allow more air... you don't need more air.

The only exception to this dynamic is at WOT wherein the total amount of air available has been diminished. In this case the power of the engine is likewise compromised. But in everyday driving, the air fuel mix always remains the same, regardless of dirty or clean air filter,... and so does the mileage.
Yes, this is true but with a small catch. You are talking about the actual volume of air in the cylinder is the same no matter what, and that is true. The ECU will always determine the amount of air pulled in and inject the appropriate amount of fuel for the equivalent intake charge. BUT, it's not about how much air is pulled in, but how easily it is pulled in. If you choke off the end of a vacuum cleaner, or restrict the intake, the motor works significantly harder to pull in the same volume of air. This brings us to the concept of "ram" air intakes in which the air is literally "rammed" into the intake instead of sucked in by the engine, this brings a small amount of efficiency with it as the engine doesn't have to suck the air in itself. So while the actual amount of air in the intake charge wouldn't change, the amount of efficiency lost from a dirty/clogged filter would have an impact. Now if the question is how much power will you gain, the answer is likely very very little to none. You will, however, gain a few miles per gallon because of the change in efficiency.

Also, I get approximately 24-26mpg driving to/from work in rush hour stop and go traffic. I get 32-35mpg cruising on the freeway for 5 hours straight.

Last edited by SamDoe1; 12-15-2010 at 03:01 PM.
SamDoe1 is offline   Reply With Quote
Old 12-15-2010, 03:45 PM   #19
Capt1014
Registered User
 
Join Date: Dec 2009
Location: Massachusetts
Posts: 167
My Ride: 2002 325xi
Combined overall highway and city I'm getting approx 25 -26mpg, 5 speed manual.
__________________
Mods, Bilstein HD Struts & Shocks, H&R Springs, F1 Racing Stage 2 Clutch & Chromoly Ltw Flywheel...more to come.


Overkill is an often underrated state of achivement!
Capt1014 is offline   Reply With Quote
Old 12-15-2010, 04:33 PM   #20
lotar_6
Registered User
 
Join Date: Nov 2010
Location: Finger Lakes, NY
Posts: 88
My Ride: '01 xi, '94 Rado
stock '01 325xi manual I got 28mpg on a 700 mile trip w/ cruise set around 80mph when possible. I've yet to measure mixed city driving.

as mentioned, start w/ a basic tune-up, scan for codes, and check for air leaks.
__________________
lotar_6 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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 On
Censor is ON





All times are GMT -5. The time now is 07:03 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use