why is my car eating up SO much gas?

[MrBimmer]

i filled up my car yesteray at around 830.. i was basically empty so i filled it up full.

checked the range on the car and it said.. +360 miles.. so im thinking sweeeeeeeeeeeet. i love it when my car has gas. lol

i drive to go pick up my little brother and the range gradually goes down and is at about +345.. get to pick up my brother and it says +305 miles.. get home and it's at +300...

turn my car on today and i notice it had burned almost 1/4 a tank.. wtf? i just got gas yesterady at 830PM and now it's almost a whole half tank gone..


i dont drive my car that hard either. always go speed limit..

im SO confused..

gas is expensive.. i dont wanna have to go fill up again a day or two after i filled up cuz my car is at half tank or almost empty.

really making me mad.

what's wrong with my car? is there anything wrong? this happen to anyone else?

[Numanoid]

Do you have a MPG setting on the OBC/ Trip Computer?

What RPM are you at when you are on the highway? What RPM do you shift at normally?

[6i9]

Maybe your fuel sending unit is defective? Mine was and it had to be replaced. For my car, they had to cut a hole in the carpeting behind the seats to get to the unit. So now theres a large piece of carpet that opens up like a door when you put the seat all the way up. This might not be the case with you though. I'm not sure

[MrBimmer]

i just dont see how it can go from +360 miles last night (granted it always is a high range when you first fill up then adapts to where you're driving like city or highway).. to as of right now.. 233 miles range..

the MPG says 19.8 MPG everytime.

when i'm on the highway.. i'd say.. going 65 at about 3000 rpm.

car's auto.. so i dont shift. lol

[Numanoid]

Ok, hmmm. I can tell you from my experience at the pump I usually get about 280 miles to go on the trip computer right after I fill up. That is when I have about a 21 MPG efficiency. If I fill up after a long highway trip the computer will show 340ish right after I fill up. It takes the most recent consumption and determines what how long the tank will last using with it.

Now I would doubt that you would get 350+ miles a tank with a 19.8 mpg consumption. 19.8 seems a little low, but you have an auto....

The best way to determine your consumption is to see how many miles you put on it before you fill up again (say at lease down to 1/8 tank.) I usually get about 250 and have about 30 miles left on the trip computer. Just drive like you normally do, and make a mental note of how many highway miles you put on.

[Numanoid]

Oh, 1 quick question. Do you reset the average consumption and speed after a fill up?

I'd reset both of those and your trip odometer to gather more data.

[SecretAznSauce]

Did you change gas stations? I think defferent stations add more additives "fillers". I noticed my MPG varies 20-30 miles per tank depending on stations. just my 2 cents. btw my driving is the same every day. 120 miles all hwy everyday

[Lawrence1]

it could be many reasons. if it keeps happening and the following itmes havent been replaced like they should, changing them out will improve your gas mileage significantly.

1. air filter
2. spark plugs
3. fuel filter
4. O2 sensor(usually your Check Engine light will come on if it's bad)
... also try running some premium chevron w/ techron for a while ... maybe a full tank with some freeway driving over 3k rpms.

hope it helps.
good luck.

[Lawrence1]

also IIRC ... autos get better gas mileage on the freeway than manuals on the E36 because of the taller gears in the auto.

... anyhow don't expect to get more than ~320 miles on a full tank(significantly less if you drive around town with the A/C on).

[FriedKalamari]

could also be the injectors, how many miles does ur car have?

[Solidhead]

26 on highway and 23 for me with the same model.....yeah it's weird, just try changing filter/plugs like it has been mentioned eariler.

[MrBimmer]

well it said 360 miles on the range.. that really surprised me.. never been that high. usually is about 320 most it ever was.. +340 after i filled up all the way.

car just hit 100,000 like 2-3 months ago.. has about 101,500 right now.

i checked the MPG and it said 19.8MPG.. does that normally change or generally stay the same? each time i've checked it is says 19.8.

only use amoco.. my dad's anal about what kind of gas we use. lol he only wants amoco premium in the cars. no clue why.

[SilverStreak]

I'm betting your MPG reading is an average from a long time running, that has not been reset in a long time. And your "Miles til empty" reading is based on calculations from immediate readings.

I'd pay more attention to the fuel gauge and less to the computer for a while, and measure the mpg yourself and see if it adds up...

[SkycityBMW]

You may have a gas leak? . . . do you smell gas when you fill it up?

I just noticed I have one. I filled up and a couple of days went by and I lost a 1/4 tank too. No puddles of gas on ground.

If so here's a DIY link: http://home.earthlink.net/~frankie66...uelsender.html

Hope it helps

[socalbimmer]

also IIRC ... autos get better gas mileage on the freeway than manuals on the E36 because of the taller gears in the auto.

... anyhow don't expect to get more than ~320 miles on a full tank(significantly less if you drive around town with the A/C on).

I get 400+ highway miles in one fill up....27-28 mpg

[Thor77]

At least in my experience, the first quarter of the gas gauge in an E36 goes the fastest. In my car, that first quarter vanishes in like 30 miles, but the tank gives me at least 255 miles of nitrous-assisted blastin around town before it turns on the fuel light. So like the smart people said, just set your trip meter when you fill up, watch your gas gauge, and see what mileage you're actually gettin.

[ekdemos]

The computer is not always right. Drive the car until the light comes on and put 10 gallons in drive until the light comes on again and do the math you get very accurate millage reading. Also take a look a your throttle body if it has some black gunk around it clean it out and that will help you out as well. also when was the last time you replaced the plugs. Always used 93+ in your car nothing less. Don't drive your car so nicely. As fo instance in my old m5 If I just putt around for a few days she runs horrible. Bmw's are made to run 5k + all day long. Ince a day run her through the gears just below redline and then run her softly. You will notice your car running better and eventhoug you hop on the gas the millage will go up. good luck.

[SecretAznSauce]

just FYI, I have own 2 325's. all hwy I get 320 tops per tank. I have owned 2 318's. I get 420 tops per tank. my 528, I get 340 per tank all hwy. Mixed driving is about 20% less across the board

[Lawrence1]

I get 400+ highway miles in one fill up....27-28 mpg

i got very close to that (~380) but that was all freeway driving @ 75 MPH constantly ... and if i were to be doing 65ish the whole time i'm sure the 400+ miles on a full tank could be achieved...unfortunately many people nowadays drive over 65(me included) when on the freeway.

*btw ... when i said ~320 i was reffering to mixed driving.

[einhander]

I made it from Sac to LA on one tank one time at a stead 72mph.


Anyway, like someone said, check the fuel filters and O2 sensor. Its not uncommon to see better gas mileage after a tuneup.

[Hollywood Hamilton]

Mine too right now. I used shitty free gas @ work and all of the sudden, BAM! 360 miles on a tank. I am going to change the O2, plugs and fuel filter this weekend. Keep us all posted

[Daved]

You don't get an expensive gas, guys, please stop complaining. It's around 2.50 US dollars a gallon here and most people don't make more than 800 USD a month.

[Lawrence1]

^ and what octane is that?


i'm guessing it's higher than the 91 we get in cali. i'm tired of people pointing to european gas prices and saying oh my... gas is so much cheaper in the US and all that crap.

it is cheaper for a reason ... i.e in cali the highest octane widely available is 91. in europe i think the lowest is 98 but i can't remember exactly.

[kal528]

Thank you all, I appreciate it taking the time to write your message thank you