M42 Gas Mileage Thread

[royalflush313]

I'm consistently getting about 23-24MPG (around 9.5-10L/100km) in my 318is.
I do mostly (85%) city driving, and I drive pretty good in terms of not going on the gas pedal all the time.

I have read many times, that people are getting 30+MPG in their 318is, mostly city driving. WTF!

I'm going to be replacing the O2 Sensor soon, anything else I should look after? (Other general maintenance like oil/filter, fuel filter etc are up to date).

So what kind of gas mileage are you getting with your M42 car?
Any suggestions for checking the possible 'bas mileage' problem?

[gazellebeigem3]

o2 made a huge difference on mine when i replaced it

[nickmp0wer]

i used to get over 30 but now it seems like im getting lower. it happend right after i put in the markd chip, got my afm wet, and i put in 19lb injectors. Think it might be the injectors?

[hamann318is]

City 28 / Hwy 30

That's about my average.

[2002maniac]

27 city, driven HARD
20 hwy

The only time Ive checked my highway mileage was on a late night trip to vegas averaging 110mph :)

[dbgrubbs]

I bought my 318is a few months ago and expected to get around 30 mpg. Ain't gonna happen! Driven nice I get 27-28mpg with about 75% highway use. Unless you're extremely light on the throttle and mostly highway, I don't think you'll see 30 mpg. Besides, even if you get 30 mpg, what kind of fun are you having? I'll settle with 25-26 with some fun thrown in thank you!:D

[kansas-ix]

90% highway and I get right at 28mpg

[royalflush313]

looks like my mileage is still low. It's not a huge deal - I used think that it was pretty good until I saw that others were getting way better mileage.

So other than the O2 Sensor, what can I look for?

[Rob]

exactly 29.5mpg for the last tank, 75% highway, 25% city, 89 octane.

[nickmp0wer]

thought you had a markd chip? and the m42 requires 91 anyways?


i think i might see if i can find a cheap AFM and see if that will fix my sudden mpg decrease. it seems to run better when its warm out. Did any one notice a decrease in milage when putting in a markd chip?

it also took a couple tries to pass emmisions due to hydrocarbons

[royalflush313]

Yah I have a MarkD chip, but the mileage hasn't increased/decreased with this chip from stock.
I passed emmissions test with flying colors.

[christophbmw]

damn! 30mpg! thats good, i get about 25mpg if im lucky....but then again 95% of my driving is on country roads and my little M42 see's redline on a daily basis. i also replaced the O2 sensor on it about a month ago (to cure an idle prob.) and didnt notice much of a difference.

Also one note, i dont want to blow smoke up anybodys skirt but i believe an internal cumbustion engine is most effeicient at its peak horsepower, so while accelerating wouldnt it be more fuel effiecient to floor it everytime you accelerate? it hasent been proven yet......what are your guy's thoughts? i do notice a LOT of SUV's accelerating very SLOW at the stop light and it bugs the shit out of me! gooooooo!!!!

[e30sd]

mixed city highway i get right around 25-26. on long drives i've gotten around 31mpg.

[Jarvis]

while accelerating wouldnt it be more fuel effiecient to floor it everytime you accelerate?

Go ahead and test it yourself. Light acceleration to get up to speed vs. WOT and letting off once up to speed, every time...

[2002maniac]

27 city, driven HARD
20 hwy

The only time Ive checked my highway mileage was on a late night trip to vegas averaging 110mph :)

I have had my cams in for a while now and my city mileage has dropped to 22-25mpg