WTF gas mileage!

[swollix]

Idk what it , but this week my gas mileage has really sucked... I only fill my car halfway, and by Wednesday I had already done so three times. My odometer only shows 250 miles.... and I have used up approximately 1.25x the gas tank... so I am getting about 14 mpg... What could cause this? I replaced the spark plugs today. The car is 200+ lbs. lighter because I have 12 lbs. race seats and no interior from the front seats back... So my mpg should be better!

[IronButt II]

Might try cleaning the HFM sensor. Those things can jack your mileage when they get too dirty...

[Garrett M]

What are you making a track car?

[HowzaM3]

How much do you step into the car if it is gutted i assume you enjoy going fast? Is the interior really 200 lbs?

[houstonm3]

i get between 18 - 20mpg city and upto 24mpg highway and i dont have any weight reduction, there's defiantly an issue.

[Garrett M]

How much do you step into the car if it is gutted i assume you enjoy going fast? Is the interior really 200 lbs?

Maybe...No spair, no trunk carpeting, carpet mat etc...

I learned that its pointless on a street car, put mine in and never looked back.

[Hammer03]

The gas gauge inside your car isnt very accurate, and filling it to "half way" could be anything from ~6 gallons to ~10 gallons (guestimates) of gas in the tanks. At least I've noticed on my 98 the first 200 miles will go by in the first quarter of a tank or so, and then the middle half of the tank will go by much more quickly, and then the last quarter will go more slowly than the middle half, but will not last quite as long as the first quarter. I usually end up around 20 mpg because of the amount of surface streets I drive on.

You might try filling your tank all the way up (until the pump shuts off, don't top off) and then drive until the tank is near empty, then fill up at the same station, and see what kind of mileage you got, checking with a more reliable measurement of how much gas was actually burned off.

[GacAttack]

I have the exact same problem. I only get about 13-15 mpg (pronounced eff-YOO-al-gor, eye-LUV-warm-wae-ther). I know what my problem is: I drive every road like it's the track. I rarely hit the road and don't get over 100mph before reaching my destination, be it 300 miles away or only 3.

Try easing-up on the right one, jiggling the knobby-thing in the console at lower RPMs, and OCCASIONALLY let someone else be the fastest one on the road. If you can do that, than you have more will power than I do.

[swollix]

My driving style hasn't changed... I used to get 19-21 mpg.... I have been going through gas so fast this week, it seems like I have a leak! It's not a track, car I just enjoy the benefits of having a lighter car and seats that actually hold you. Plus I got rid of most everything unnecessary:
http://img.photobucket.com/albums/v344/swollix/car/CIMG0494.jpg
http://img.photobucket.com/albums/v344/swollix/car/CIMG0495.jpg
http://img.photobucket.com/albums/v344/swollix/car/CIMG0499.jpg

[the Locust]

me too! I also noticed a drop in MPG/total miles covered. wtf...

I used to average 280-310 filled-to-empty, but this week it's around 250-260. Possibly because of the snow that hit last week but I filled up after the snowstorm..

[PointMEby]

When was your 02 sensor replaced? Most likely its slowing down and its not slow enough for the computer to read yet. I bet this is your issue. I'm getting 320 in the city cammed, tuned and not driving slow

[swollix]

When was your 02 sensor replaced? Most likely its slowing down and its not slow enough for the computer to read yet. I bet this is your issue. I'm getting 320 in the city cammed, tuned and not driving slow

Hmm I'll have to contact the previous owner...

[Tim95M3]

weight reduction ftw! lol

[swollix]

weight reduction ftw! lol

mpg reduction for the lose!

[swollix]

Any other suggestions besides dirty HFM, or O2 sensor?

[300HURST]

Go back toing the basics. Its probably something simple. easiest is check your exhaust. Run your finger inside. If its dry black, too much gas is being burned. If its wet black, you got big problems because oil or coolant is getting into the combustion chamber. bad combustion=bad MPG. If exhaust is clean, tell your friends to stop playing jokes on you. (They are taking gas out of the gas tank when your not looking.) If exhaust is dry black, then either O2 sensor, thottle positioning sensor or other sensors are bad. Easy fix is clean all sensors is to spray a whole can of fuel injector cleaner in the engine (slowly until you hear the engine stumble don't do it too fast). If that doesn't help, check the airflow sensor. I think you have to be careful cleaning these, not sure. If that doesn't help, check spark plugs, wires, air filter, fuel filter....maybe theyre just crappy and need to be changed. Maybe there's a obstruction in the air passage or fuel lines. The computer compensates for these problems by bumping up the fuel into the engine. All ECM's are designed to keep the engine running as long as possible.hope this helps

[swollix]

Where would I spray the fuel injector cleaner?

[EnderG60]

dude if your getting any oil in the cylider it will totally @#$% your mpg. Fix that damn valve cover gasket and get some new spark plugs.

[QtheGenius]

last time i was on the highway, i was going roughly 280 miles and I averaged 73 mph at 27mpg, according to my little computer thingy-ma-bogger. city driving, i've never seen my car go under 22mpg, so these cars can do great mpg on the highway, but once you start goofing around (i know, it's really easy to do that in these) it can start to drop off.

[DrifterX27]

air filter? a bad one does jack up mpg

[antik]

Check your tire pressure.
Replace fuel and air filters.
Fix leaking valve cover gasket.
Fresh plugs (single electrode copper plugs).

[MarylandDakarM3]

wow.. i still get 29.7 mpg.. =).. and this is in winter!.. all i do is go to school and come back home.. i dont know how the heck u guys get bad ass mileage. and my car had over 130k miles.. so, it should be worse then u guys. but, ya, its w/e.. i always have my eye on the the needle thing that tells u how much mpg u r using.. best thing bmw has ever made!> =)..

[swollix]

It says in 1st post I put in new plugs Thursday. I just put in some fuel injector cleaner...

[Seruy]

i always have my eye on the the needle thing that tells u how much mpg u r using.. best thing bmw has ever made!> =)..

Gotta disagree with you mate, I'd rather have the oil pressure gauge, like in UK!!! That gauge only flaps around for no reason, annoys the hell out of me, useless piece of junk.

I think I'm going to take it out, sell it on ebay and use the money to buy booze and make myself feel better.

[Seruy]

On another note, I do get about 16 mpg in the city, I think it might be time for a tune up. Although, O2 sensor might be the culprit here - over $100 for one, scheisse!

[nukeduster]

Gotta disagree with you mate, I'd rather have the oil pressure gauge, like in UK!!! That gauge only flaps around for no reason, annoys the hell out of me, useless piece of junk.

I think I'm going to take it out, sell it on ebay and use the money to buy booze and make myself feel better.


+1

[racer m]

clogged injectors,

anyway i get about 19-22 in the city and about 27 -39 mpg

[calypso]

Why in the world would you drive around on the street like that?

[swollix]

Why in the world would you drive around on the street like that?

Why not? I am comfortable, and I am not putting anyone in danger so why not? I never use the back seats , and now I have a legitimate excuse to keep fat people out. The seats only fit up to a 34" waist.

[SoCal3000]

wow.. i still get 29.7 mpg.. =).. and this is in winter!.. all i do is go to school and come back home.. i dont know how the heck u guys get bad ass mileage. and my car had over 130k miles.. so, it should be worse then u guys. but, ya, its w/e.. i always have my eye on the the needle thing that tells u how much mpg u r using.. best thing bmw has ever made!> =)..

29.7mpg????? Do you drive down-hill both ways to school? :lol

I get 18-19mpg....but even on the freeways I keep it in 3rd/4th so I can pass jackasses in the 'fast' lane. Gotta keep it in the high RPMs FTW!!!

SoCal

[EnderG60]

Why not? I am comfortable, and I am not putting anyone in danger so why not? I never use the back seats , and now I have a legitimate excuse to keep fat people out. The seats only fit up to a 34" waist.

:lol AHAHAHAH sorry no fat chicks, you dont fit!:alright

And yeah but if your still leaking oil on the plugs you can still be screwing things up.

Better fix it soon gas prices are on the rise:(

[swollix]

I spent $100 this week! I usually spend $60-80...



:lol AHAHAHAH sorry no fat chicks, you dont fit!:alright

And yeah but if your still leaking oil on the plugs you can still be screwing things up.

Better fix it soon gas prices are on the rise:(

[e30'd much?]

i get ~27 or so freeway with a 3.73 rear end...

[300HURST]

If you don't even know where to spray the fuel injector in, then forget everything I said earlier and bring it up to a mechanic.

[e36 Irfan]

i dont kno if miles matter or not but i have 84k and i get 18-22 in city and 25-27 on highway
but then again i am 17 and sometimes i am a ricer

[racer m]

sometimes i am a ricer


lol wut!!!

[Danethomp]

I drive a 97 auto w/ 173k miles and average around 16 mpg mostly city driving. This seem normal?

[Jahseso]

i think my old mustang got better than that dane...

[Danethomp]

i think my old mustang got better than that dane...

so maybe o2 sensor? plugs? dirty hfm?

[BinhM3]

chk fuel filter, air filter dirty, oil change, higher octane gas...

[racer m]

I drive a 97 auto w/ 173k miles and average around 16 mpg mostly city driving. This seem normal?

lately i have been managing only 18-20mpg in the city(yeah its a slushbox, time to drive like grandma so i can get 23 in the city :()