Not so great gas mileage....

[bmwm3n528]

Trying to figure out why the 325is isn't getting such great gas mileage...wondering if there's some deal with the o2 sensor, throwing out too much fuel or something.

I've just rubbed my finger along the exhaust once in a while, getting the carbon off ...and it feels quite wet. So, wondering if it's burning some gas or something.

Any ideas, i'm a n00b in this dept. ...so any clues are helpful.

[///M42 sport]

I get 17-18 around town in my 325i.

[Rob]

mileage has as much to do with driving style as mechanicals. an m20 is not a honda 4, especially around town

[kylebes1]

my tips are always black, cannot figure y though :twisted:

[bmwm3n528]

Well, not exactly sure what i'm getting...not checked the OBC, but just noticed how quickly i used a 1/4 tank of gas today....it was WAY too fast. Wasn't driving hard or 'throttle jockeying' either.

[Rob]

I wouldnt trust the OBC.

Fill up, reset the trip counter in the gauge cluster, empty tank, refill, check odo, do the math

[bmwm3n528]

math

...uh oh.

[Kondour]

and thats not gas on your exhaust tips... it would of already burned... 12+ year old motor= not fuel efficient.

[Ryan Stewart]

wter vapor is a common side effect of combustion.

[bmwm3n528]

Re: Not so great gas mileage....

i'm a n00b in this dept.

[kylebes1]

would sooty tips be a sign of fuel pressure beign to high?

[rwh11385]

Trevor, I'm in the same boat. Like 16mpg when I was getting 19/20 a lot. And somehow Nando is his slushbox iX gets like 22+ or something......

anyway, I am replacing my air filter which is a little dirty, going back to the stock airbox and intake setup....and replacing my spark plugs which looked messed (short period of running M30 AFM without new electronics, because no one knew for sure if was alright.....and then the AFM tuned incorrectly....too rich didn't help any)

Basically, if you didn't break a rocker arm.....it might just be issues like that. Dirty air filter, messed up spark plugs, bad 02 sensor.....whatever. I'm aiming for 22mpg, hopefully, if I get my shit running right again.

Oh, driving style kills me. Somehow I think I have to go to 6000+ every shift.

[hamann318is]

I still manage 29mpg even when I drive hard. The magic of the M42. ;)

The first thing I'd check is plugs, and maybe goto platiniums. I've heard good things gas mileage wise, but as you know lots of people don't. I'm running platiniums with no problems.

[bmwm3n528]

I still manage 29mpg even when I drive hard. The magic of the M42. ;)

The first thing I'd check is plugs, and maybe goto platiniums. I've heard good things gas mileage wise, but as you know lots of people don't. I'm running platiniums with no problems.

Well, i've got new plugs...replaced the platinums, cause of what i've heard about them not running so well with m20s, or with most BMW motors in general.

[UNHCLL]

it could also be the fault of bad sending units for fuel level.
sometimes my gauge tells me I went through 1/4 tank in 10 miles