HELP- Horrible Gas mileage!

[spork]

Greetings everyone-

I have a 2005 3.0 X5, 140k on the clock. In excellent condition.
[B] Im getting 13mpg- all around driving (not a lot of highway) and I am NOT a lead foot.

I have changed the fuel filter, air filter, I use super unleaded, I raised my tire pressure to 41#, I checked the spark plugs (the NGK 4 prong) and they seem fine but I will admit I could/ should change them.

13 MPG!

Shouldn't I be getting better gas mileage? What am I missing? What should i do?


UPDATE- I live in San Francisco. Car just passed smog testing with flying colors ( no air leaks, etc), The cooling system was recently rebuilt- car runs cool. I am a good wrench- been working on cars & motorcycles for decades



Thanks for all suggestions/ insights.

[andrewwynn]

Winter gas formulation?

I usually get about 21-22 highway and on a trip on the freeway driving an indicated 75-80 (actual 72-77), I was getting a crappy 18-19. Didn't change anything on my car just noticed that the highway mpg is crap. Some days I get 23-24 but haven't seen those since fall.

Do you live where they use winter blend fuel and if so can you drive to where you can get apolitical fuel (no pork funded ethanol mix). I use an app "pure fuel" to find stations that sell non diluted fuel.

Oh: random crappy performance: check your DISA valve. Be very careful removing there is a little pin that falls out it's steel you don't want it falling in the engine!

I have a DIY how to repair for 10¢ vs replace for $225.

[upallnight]

Originally Posted by andrewwynn

Winter gas formulation?

I usually get about 21-22 highway and on a trip on the freeway driving an indicated 75-80 (actual 72-77), I was getting a crappy 18-19. Didn't change anything on my car just noticed that the highway mpg is crap. Some days I get 23-24 but haven't seen those since fall.

Do you live where they use winter blend fuel and if so can you drive to where you can get apolitical fuel (no pork funded ethanol mix). I use an app "pure fuel" to find stations that sell non diluted fuel.

Oh: random crappy performance: check your DISA valve. Be very careful removing there is a little pin that falls out it's steel you don't want it falling in the engine!

I have a DIY how to repair for 10¢ vs replace for $225.

Is there a winter in SF CA? I thought it was either spring or summer.

[Effduration]

Ethanol gas could be part of the problem. But I wonder also if an air leak is causing the engine to compensate by increasing fuel in the air/fuel mixture and the car is running rich?

OP- I don't know you're experience level. Maybe your best bet is to bring it to a good independent BMW specialist and have him/her take a look for fuel robbing issues. If you attempt yourself you may just end up throwing parts at it.

I would - in approx order:
try unmixed gas
smoke test the intake line & check for leaks
make sure spark plugs are fresh
unlock the OBD and see what temps the car is running at (open t-stat?)
get clean air filter

[andrewwynn]

Open tstat caused me bad mpg for months.


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[spork]

UPDATE- I live in San Francisco. Car just passed smog testing with flying colors ( no air leaks, etc), The cooling system was recently rebuilt- car runs cool. I am a good wrench- been working on cars & motorcycles for decades

[Overboost]

Running cool is a problem. The M54 should be running at 90C warmed up. You should check the actual values in the hidden menu or a proper scanner for coolant temperature as the cluster gauge is buffered by 40C.

[andrewwynn]

+1. The temp indicator on dash is quite far from a gauge. Mine showed perfect noon for months but never got close to closed loop.

Have you checked the DISA valve? ours failed about 130 and 160,000 mi.

I rebuilt mine with aluminum and titanium. Fantastic repair kit for 1/3 replacement and way better.

I rebuilt wife's with a 6/32 screw a couple nuts and some heat shrink tubing. (20¢ perhaps of hardware that was already laying ae9und )

[oldskewel]

Originally Posted by spork

Greetings everyone-

I have a 2005 3.0 X5, 140k on the clock. In excellent condition.
[B] Im getting 13mpg- all around driving (not a lot of highway) and I am NOT a lead foot.

I have changed the fuel filter, air filter, I use super unleaded, I raised my tire pressure to 41#, I checked the spark plugs (the NGK 4 prong) and they seem fine but I will admit I could/ should change them.

13 MPG!

Shouldn't I be getting better gas mileage? What am I missing? What should i do?....

I've got a 2001 3.0i, thought exactly as you do now after I first got the car about 5 years ago. Changed O2 sensors, spark plugs, filters. Since then have done a top end rebuild.

EDIT - also, I have a pretty new DISA valve, installed by the dealer while the PO was replacing a ton of other things. I rebuilt the VANOS while doing the engine work. Virtually anything in my car that could affect MPG is new/rebuilt/working perfectly. My alignment is good too, although a bad alignment can affect MPG as energy is needed to continuously scrub off the rubber. Never a problem on a smog check, etc.

Car runs perfectly. Still about that MPG.

I think it gets up to the higher teens on the rare occasions where it gets some good cruising miles on the freeway.

So your car sounds normal to me.

[dkl]

OP, 13mpg sounds about right for our CA winter blend and mostly city driving in SF. I have 147k on the clock on our '04 and it's averaging a bit under 16mpg with 60% Highway. I even rebuilt the vanos seals at ~90k and just renewed my cooling system (T-Stat, waterpump, expansion tank, hoses) 2k miles ago.

Oh...I also just passed SMOG without issues