Fuel Economy?

[e30Andym42]

I have a fuel efficiency problem.  Driving very fuel efficient most of the time, I got to 210 miles on a full tank of 93 octane.  With another full tank of 93 octane from the same gas station, and driving like a maniac all the time, which was alot of fun , I got to 190 miles.  I filled up both times using about 12.3 gallons to fill it.

There's no way in hell I got about 17 mpg driving fuel efficiently.  I didn't touch the highways, so I accelerate alot, but still.  I got 15.4 mpg driving fuel unefficiently.  There's also no way that I only get 1.6 mpg more by driving fuel efficiently.

Or is that just how it is?  What's wrong, O2 sensor??

EDIT:  Where does the instant mpg gauge in the dash measure from?  Not that I cruise all that much, but when I am it says I am getting 40 mpg, which I think can't be right, but then again I am the one asking questions...

[Sophia69IS]

I do not think I understand the question throughly. Are you asking how to get better fuel economy?

[xwill112x]

yes, you are getting shitty gas milage if thats what your asking?

these cars get up to 30-35 mpg with good o2, and air filter, and not floored alot

[3seriesNut]

i filled up yesterday and since then ive driven 235 miles and im just under half tank. i would say your milage sucks dogs ass.

[Hodge]

I might need a new 02 sensor....Seems my mileage hasn't been the greatest lately.

Last week I filled up @ 397 miles with the light on and about 3 gallons left.

I guess that was about 27-ish MPG city driving.....and not very "right foot conscious" eitehr, if you know what I mean

Today I filled up at 376 miles and about 5 gallons left.

About 200 of that was highway driving, and again mostly not watching my right foot. That about 30 mpg.



Ok maybe I am not doing so bad with the DASC and all.

[3seriesNut]

ive got trouble keeping my foot out of the throttle personaly,my car sees 7k rpms daily lol

i changed the o2 sensor when i bought the car so that may verry well have some effect on milage too.

[quinn11m20]

I average 340 miles from fill to light. I know that my O2 sensor is bad and I can't get more than 250 to a tank. I am changing my sensor and heater relay this weekend. I know for a fact it will improve. BUT!!! I believe since I wrapped my headers my O2 sensor won't last as long. So I might have to replace more often. Oh! well.

[BraveUlysses]

i filled up yesterday and since then ive driven 235 miles and im just under half tank. i would say your milage sucks dogs ass.

Estimating your fuel usage based on an E30's flaky gas gauge is laughable. The only reliable way to estimate fuel consumption is to divide the miles traveled by gallons filled up, preferably at the exact same pump.

[tjts1]

Is everyone here incapable of dividing the number of miles traveled since your last fill up, by the number of gallons it takes to fill the tank again? Reading this thread is like taking crazy pills.

I have a fuel efficiency problem.  Driving very fuel efficient most of the time, I got to 210 miles on a full tank of 93 octane.  With another full tank of 93 octane from the same gas station, and driving like a maniac all the time, which was alot of fun , I got to 190 miles.  I filled up both times using about 12.3 gallons to fill it.

There's no way in hell I got about 17 mpg driving fuel efficiently.  I didn't touch the highways, so I accelerate alot, but still.  I got 15.4 mpg driving fuel unefficiently.  There's also no way that I only get 1.6 mpg more by driving fuel efficiently.

Or is that just how it is?  What's wrong, O2 sensor??

EDIT:  Where does the instant mpg gauge in the dash measure from?  Not that I cruise all that much, but when I am it says I am getting 40 mpg, which I think can't be right, but then again I am the one asking questions...

Your car is rated at 17mpg city. What did you expect?
http://www.fueleconomy.gov/feg/2008car1tablef.jsp?id=7641

[Sophia69IS]

Wow, I have a hard time believing 397 miles on a tank.

I calculate around 22mpg for mostly city driving, and not driving like an asshole.

I will admit I'm not an authority on such things. So perhaps someone can answer my humble question of how does an 02 sensor make such a big difference in fuel economy? I mean I understand that when you give your car more air in compensates with more fuel making a gas pedal actually an air pedal. But how exactly does an 02 sensor come into play here?

[1991 E30 M42]

I went 370 miles on my last tank without the gas light coming on don't know what kind of mileage that was because I didn't fill up all the way, but my last tank I went 330 miles on 9.5 gallons.

[BraveUlysses]

Wow, I have a hard time believing 397 miles on a tank.

I calculate around 22mpg for mostly city driving, and not driving like an asshole.

I will admit I'm not an authority on such things. So perhaps someone can answer my humble question of how does an 02 sensor make such a big difference in fuel economy? I mean I understand that when you give your car more air in compensates with more fuel making a gas pedal actually an air pedal. But how exactly does an 02 sensor come into play here?

http://en.wikipedia.org/wiki/Oxygen_sensor#Automotive_applications

O2 sensors are a wear item and need to be replaced if they aren't measuring correctly.

[3seriesNut]

Estimating your fuel usage based on an E30's flaky gas gauge is laughable. The only reliable way to estimate fuel consumption is to divide the miles traveled by gallons filled up, preferably at the exact same pump.

i didnt say it was a exact estiment. im just going by what the gauge says. to be honest i really dont worry about my milage becuase my job mays me for fuel used and wear and tear on my car.

[93bmw318i]

never posted before...  just reading some posts on the 318s mpg ,check this out!
i drive my 93 318i 5spd 45-50 miles a day city highway combined  .. black on black type 73 wheels 215 50 17 tires ebay chip 97 m3 springs electric fan 4 hole injectors {out of fox body mustang} .. ive bought this car @ 193000 miles with no info on the car  i live in phoenix yes its hella hot i  run my ac most of the time  i avage 24.5 in the summer 26-27 in the winter time no ac, my car now has, ready! -----237303 miles no rebuild!! still runs great and pulls hard to redline and  still get the same mpg ,uses just a little oil ,even when i drive hard it never drops below 22mpg not bad for a motor with the miles it has ..........ps i have never replaced the o2 yet ....I love this motor i hope to
300K out of it   !will see!

[stevohill]

I don't know what you guys are doing that get low 20 mpg, but I drive my car hard every and just filled up today and mpg average was 29.7. Most I've ever gotten out of a tank was ~380 miles and I only filled up a hair over 13 gallons.