edhonda09

I bought 2009 Civic LX-S and love it except for the gas mileage. It seems every time I look at the gas gauge it drops a notch. I have done what the dealer service department told me about filling the tank. That is fill untill the pump clicks off the first time. Then record the gas it took to fill the tank and then divide by the miles driven. The Honda service dept checked my complaint out and said everything was ok. They even did a "relearn of the computer system to see if anything was out of specs. No problem found. The service tech said there was not much more that they could do. Now what!!

The service tech said to drive the car 100 miles, fill the tank and see what milage I got.

The last time I filled up the tank I had driven 118.3 miles 40% town and 60% on the highway. The gauge showed the tank was about half full.
I filled the tank to the first click as instructed by Honda service. It took 4.833gals to fill up. then I did the math.

118.3 miles divided by 4.833 gals to come up with 24.4 mpg. Something is
not right with this car. I should be getting at least 29 combined. Also. I use
Shell gas regular 87 octane. I bought the car because it was supposed to be so fuel efficient.

Does anyone have an suggestions to help me out. I'm at a loss. Thank you!!

gearbox

iTrader: (95)

seems a bit low, but it depends on driving style and environment. winter you will always get bad mileage due to the colder air. when the engine fully breaks in after 20k miles, you will see the best mpg numbers.

odysseus

I have a similar mileage question. About 2 weeks ago, I bought a used 2006 Civic LX from a local Honda dealer. It had a 150 point checkup. I filled it with a tank of 87 octane Shell gas, and since then I've driven 90 miles -- and the gas gauge is one square above 1/2 full.

Now I take short trips and temperatures have been between 24 degrees and 40 degrees or so, but the 2001 Civic EX that this 2006 Civic replaced got 24-25 mpg under the similar driving conditions.

Could something be wrong with this car? If so, what would it be? The car has a 1 month powertrain warranty, so I'd want to take advantage of it soon.

gearbox

iTrader: (95)

its possible the fuel sender is faulty and not reading the correct gas level. have you actually measured mpg by using a whole tank til its empty, then fill it to full and see how much gas you put in? then divide miles/gallons. even a working gas gauge is never exactly correct. ive had times where the needle was on E and gas light still was off, but there was barely 2 gallons. other times it drops faster near the bottom and comes back up depending on how the car sits.

odysseus

I guess the sender could have a non-linear response. I filled the tank, and have been driving it since then. I'll be able to make the true mpg calculation once I fill it again.

If it were an engine problem, would there be an error code?

TRIZ

iTrader: (14)

You'd have a CEL if the computer detected anything wrong with your car. If there is something wrong, your ECU hasnt noticed it yet, hence no code.

Do what gearbox suggested- fill it up all the way, reset a trip meter, drive it till its empty (or damn near) and see how much you filled it up with- then do the math.

I second the fact mpgs suffer when its colder out. Not only do our ECUs dump more fuel for the denser air, but additional additives in the fuel dont help.

gearbox

iTrader: (95)

yeah i usually get 10mpg less in the winter.

leo122

it has everything to do with driving style. I used to work at a dealership in the service department and there wasn't one day where someone wouldn't complain about their gas mileage. You can't expect to drive really fast accelerating heavily and still get the manufacturer mpg rating. Those tests are done at basically posted speed limits you would basically have to drive at that to get the expected gas mileage.

odysseus

I know, but I should expect mileage in the 2006 Civic LX to be as good or better than in my 2001 Civic EX, shouldn't I?

gearbox

iTrader: (95)

assuming the same driving style and location and time of year, then yes.

TRIZ

iTrader: (14)

^ You would think so since its newer, but it is a different engine.

AND

The way MPG was measured on the 7th gens and the new standard are different. I havent read specifics about the change in methods for calculating but I thought the newer standards were supposed to more accurately show mpg's.

AND

The driving style differs along with the actual weight of the car

AND

.......

There are a lot of reason why your MPG's could be different. You may have a problem though.





What I would do... since its impossible to drive the exact same any two times when doing any city driving.... let the car warm up and head out to the highway to fill up at a gas station right by the onramp. Drive 100 miles without using any electronics sucha s the radio, car chargers, amps, AC/defrost, etc. Then fill up at a gas station next to the highway and calculate MPGs. (the best I ever did was 41 doing this)

Then on the way back, use electronics, put the car in defrost with the ac on, dont use cruise control, basically drive like your normally would. when you get back- stop at that first gas station and fill up and calculate mpgs.

Then do this same test again when its spring/summer (aka nice out). This will be the true test to determine whats going on with your mpgs!

You can probably do this whole test (over both seasons) with only paying for one complete tank of gas- the cost will be much less then trying to aimlessly fix this and try that when you dont need to.

Also.. another thing. Not only do they use adatives in the winter, but if your like me, your car fogs up and you have to use the defrost- which casuses the AC to kick on, and that kills MPG's.

odysseus

I was just wondering which of the more obvious engine problems could cause poor mpg. I have a one month unlimited mileage powertrain warranty, so if there were a problem, I'd want to get it fixed before Jan. 31.

TRIZ

iTrader: (14)

Bigest problem- a crack in your gas tank, or a leak in the line.

If you have a high idle, your wasting gas- idle should be about 750rpms- not over 1,000. High idle means your throttle body isnt fully closed, and the injectors are pumping more fuel to keep the air/fuel ratio correct.

Since your car is used, maybe the person before you did some modifications... a hidden piggy back with some wacky settings would also drop mpgs.

Aside from that.. carrying too much weight in your car- like a trunk full of crap... tires that arent inflated properly.. driving style... stomping on the gas, doing lots of gas/break. Mainly, the biggest thing that will kill your MPG would be using the last two settings on your dial that force the AC on.

edhonda09

I have filled the tank twice since my frist post. I did as the dealer suggested. Fill to the first click and drive 100 miles.
Result: 118.3 miles 30% City 70% Highway - put 4.833 gals to fill - got 24.48 mpg

Result 2: 101.6 miles 90% City 10% Highway - put 4.907 gals to fill - got 20.705 mpg

Both fill ups using Shell 87 octane. I don't understand why I don't get better mileage.

Devani

iTrader: (2)

well, it's brand new car and if your Honda Tech checked out the car okay, I would have to say that it's your driving style and environment....but mostly it's driving style...I have 09 SI sedan and my mileage in the winter is 29mpg in summer i usually get 31-32mpg....

you didn't tell us where you are and how fast you were driving....the car is fuel efficient not the driver....

gearbox

iTrader: (95)

yeah ive gotten anywhere from 15-42 mpg depending on driving style and conditions. to give you an idea how big the range is. now if you are gently taking the car up to speed, holding at 65mph, and cruising on a flat highway in the summer for 100 miles, and then getting only 25 mpg, i would say there is a serious problem. have you had the alignment checked?? i wonder if your rear tires look like this / \ instead of this | | and thats why the poor mpg. alot of newer civics have rear control arm issues.

jmiked

You might also check and see if you are running a gas/ethanol blend. Around my area, the stuff i get is E10, 90% gas, 10% ethanol. Some places have E25, which is 25% ethanol. The more ethanol, the worse will be your gas mileage. Some people have claimed a 20% reduction in mileage. I have no personal experience, that info is from the net.

I average 26.4 mpg (mostly city) with my 2007 LX automatic, and haven’t been on the highway for a long enough distance to know what I would get as highway mileage.

edhonda09

I live in North Carolina. City speed is 35 mph and that's what I do +- 5 mph. I do not have a lead foot. On the highway between 65 and 70 +- 5mph mph depending on the speed limit. Of course you have to excelerate to pass another vehicle. Over all I take care of my car and try to obay the rules. So I don't believe it's my driving style.

gearbox

iTrader: (95)

only other thing i can tell you is the engine needs to break in more. i got lousy mileage when the car was new as well. not until 20k did i see some good improvement.

Devani

iTrader: (2)

it is driving style because I frequently drive my wife's CR-V...she drives more carefully and slower than me but she gets worse mileage than me....how???? that's the difference....she doesn't have lead foot...she only does 65 mph on highway and always do speed limit....

when I totaled my EX 01 Civic, I drove my wife's CR-V almost two months, CR-V has mph indicator and whenever I drive i used to get 24mph+ on them...now it's 22.4mph she drives 95% of the time....

smbdyshero

This was gonna be my .02 as well. My 07 Si gets right at 23mpg with E10, which is the city estimate on the window sticker of the 09's. It's still a long term average, though. Ethanol has great octane ratings, but horrible mileage ratings. I would imagine everyone in the country has a little lower mpg than they did last year. You should probably wait until the weather changes to see if mpg's improve.
Still, make sure the dealer is documenting everything, cuz if there's a paper trail, you always have a case.
Also, make sure you search all over this site and 8thcivic.com for info from other people in your area with similar problems.
Never hurts to make friends with the Honda service advisors either.

scriptora31

Hi all,
Glad I came across this thread, as I have been having a similar problem with my 2006 Civic LX. I moved from Colorado to Missouri in August, and for the past several months, I've noticed a precipitous drop in my gas mileage. I was getting 30 city, 39-40 highway consistently for three years, using 85 octane. Now, I'm lucky to get 22-24 city and 30 highway with 87 octane. It's an automatic transmission.

This has been a problem in everything from hot, humid weather to frigid, dry weather. I am not a lead foot and I am driving the car the same way I've always driven it, so it's not my driving habits. If anything, I've been more cautious because of this, but it's getting worse. I'm looking at 21 mpg on current tank, and that includes about 30 percent highway driving.

Here are my three variables: 1) I moved to a lower elevation with more humidity. 2) I have a hilly neighborhood now and I'm going up more hills at low speeds. 3) I got a new battery and new tires (after this problem started, but still).

Any thoughts? Could those things be to blame for a 10 mpg drop? I am worried it's a riding brake, fuel pump problem or a computer problem, like too much gas going into the tank at startup and I'm burning it off. Would you take it to a shop and have it looked at, or chalk it up to my Civic getting older?
Thanks for any advice you can give!

gearbox

iTrader: (95)

tires could be to blame, some people have lost nearly 10mpg changing their tires on the hybrid civic. low rolling resistance means alot. also low altitude means alot more oxygen, so the ecu compensates by dumping in more fuel. at higher altitude, air is thin and less fuel is needed. if youre worried about brake drag, jack up the car one side at a time and spin the wheel (in neutral). if you hear scraping or wheel wont turn, somethings wrong. have you had alignment lately when changing tires?

scriptora31

hmm, maybe it's the ecu. It would make sense. I did have the alignment done when I got the tires done in Oct. But this started before I got new tires. I have a regular civic but my dad has the hybrid version, and he came up with the dragging brake theory. I will try the jack test, but the ecu thing makes sense. When I first fill up, the gas indicator blocks disappear quickly, like with every few miles. Then it evens out and when I am getting close to empty they disappear really fast again, like it is firing in more gas than it needs.
Is it expensive/ complicated to fix the ecu? Hopefully not. Thanks so much for your insight, this has been driving me crazy!

gearbox

iTrader: (95)

no im saying the ecu is a normal function to make the motor run properly. it just varies the amount of gas depending on outside conditions and air quality. also how are you measuring mileage? do you fill it up til the pump clicks off, then drive til its near empty, then fill it up to full again, take the miles you drove divided by the gallons you pumped in? if the fuel gauge doesnt seem to be accurate, its prolly a bad fuel sending unit. i had the same issue and it would read empty even tho i still had 5 gallons left.

scriptora31

Well, I wonder if it is something else then. Yeah that's how I measure mileage -- fill up when empty, wait until it clicks off, use until empty, fill up again and divide miles driven by gas I used. That's what I have always done and it used to be 30 city, 40 highway; now it's 20-22 city and 30 highway at best. Also I was in my friends civic about a week ago and noticed how much more peppy his car was... my car used to be like that and its not anymore. It's only 3 years old so it's not like it should be so sluggish already. What about a fuel pump issue? it's not leaking or anything like that, it's just really bad miles per gallon.

edhonda09

Also adding to my first post. I got a loaner car while the dealership did a re-learn of the computer system. The loaner civic seemed to have a lot more get up and go when you stepped on the gas. So much that it sat me back in the seat and startled me. My 09 civic also seems to be sluggish from stop to excelerate say from a traffic light, and i'm still getting bad milage. Now i'm keepng a record my mpgs from this websites page so i can bring the info to the dealer the from next time i go.

So from what i've read from your replies. I may have an issue with the:
Fuel sender
fuel gauge
throttle body not fully closing
brake drag
ecu

any other ideas to add to the list? Like i stated i live in winston salem nc.

Thanks everyone for your input

Metalhead852

I have an 06 with 41K miles and I'm getting 24-25 mpg normal driving. About 50/50 city/hwy and 32 mpg highway only. So I dunno.

Trek4ward

I bought an 06' EX Coupe (manual) a few weeks ago and decided to check the mileage with a fill-up and the odometer. Just prior to this test I did two things however: I reprogrammed the defroster via the sticky to turn off the A/C and replaced my plugs. I came out at 34 MPG with 80% highway, 20% city. Not bad considering the cold temps and winter gas in Maryland.

johng35

I think the car responds to how it driven - stay out of Vtec and the milage can be awesome.
Long distance cruising at constant speeds (even 60-70MPH) and the tank will seem like's it 20 gallons- not 13.

Drive like me ( I do like the sound of the engine !) and it can be unimpressive for a 1.8. (Seems like my old 3.8 Ford).
Also the tires can make a noticble difference, which I thought was just BS in the tire sales brochures.