MPG question

D15, D16, D17 and Mini-Me swaps
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MPG question

By dawg316
- Fri Jan 20, 2012 1:11 am #291104 hey guys i recently got a new civic. and it only dose 17-18 mpg. changed the fuel filter , sparkplugs, airfilter, ect.

i do keep my foot in it at times but 17mpg sounds a little low. and yes i did calculated it right. any thing i can do to improve my mpg?

dosnt seem like im running rich so i done know if i should change my o2 sensor or not.
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By Ajax1989
- Fri Jan 20, 2012 2:46 am #291120 What u need to do is take a gas can with you full of course and fill up the tank and reset UT odometer and drive till u run out. I had this same problem but it was my fuel gauge .. it gave me the wrong reading.. I was getting average 14 MPG I did this and I started averaging 27-30 MPG so I'd fill up every time I was close.. only ran out once.outta 3 yrs

By dawg316
- Sat Jan 21, 2012 6:37 pm #291369 ive just been filling it up. reseting the odo. then driving it. when i go to fill it up again i right down my kms driven then do the math on how many liters i put it.
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By Ajax1989
- Sat Jan 21, 2012 7:15 pm #291372 umm that doesnt sound rite.. i think your cluster is messed up.. no way in hell any civic should be gettin 17mpg.. even with a blown motor lol

By ccornewell
- Sun Jan 22, 2012 2:03 pm #291439 Just something I noticed, you fill up measuring liters, your odometer measures in km, and you posted a question in reference to miles. are you converting kpl to mpg properly? http://www.mpgtokpl.com/ My 4 door sedan gets 32 mpg with warming up in the winter, that transfers to 11.33 kpl.
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By egcivicboy
- Sat Jan 28, 2012 7:03 pm #292400 I'm having a problem sorta like this.. when i first got my hatch in august i was getting around 230-250 miles on a tank and i would fill up as late as possible and put around 9 gallons in. that works out to around 27mpg. but recently i've been getting worse and worse mpg. on this tank it looks like i'm onlly gonna get around 200 miles. I do need an alignment but i've needed that ever since i got the car, so i don't think thats the problem. And I don't have a cat so that's not it. Should i replace my 02 sensor? or any other ideas?

EDIT-- engine is a D16z6. only engine mods are intake and exhaust.

By dawg316
- Sat Feb 04, 2012 5:58 pm #293311
teal_dx wrote:Maybe it could be a combination of things?
Example: o2 sensor going bad, bad alignment, low tire pressure, clogged cat...


my cars dumped. toe is fine, the cambers a lil wacky from tire to tire. rangine from neg 1 to neg 2 on some tires, have nitrogen in my tires havnt checked them but worth a shot. ( new rims and tires coming this week :D )

dont know about my cat, passed aircare easily and it seems like a have good power so i think its still good, dont know about my o2 tho. old car lots of km, but havnt noticed it running rich or lean.

By dawg316
- Mon Feb 06, 2012 7:04 pm #293537 my idle seems a little low when warm also. cleaned fitcv set the screw in, rewinded it about 1/4 turn. cleaned the iac. fresh coolant and bled it ( had to get ready for a canadian winter) and all that got rid of my surging idle

i have a suspicion that my fuel pressure regulator might be going bad then, the symptoms seem to line up with using more gas, low idle ect.

previous owner said he changed the fuel pump before and i also just recently installed a new fuel filter. worth a shot at using a new FPR ?

By ccornewell
- Mon Feb 06, 2012 10:34 pm #293570 I would follow the procedure to troubleshoot a bad regulator. I have this allergy that stops me from throwing money away by replacing good components. It helps the bank account stay in the +......

By dawg316
- Wed Feb 08, 2012 10:50 pm #293954 tires where at 30 psi. now bumped up to 40psi.

not gonna grab a new fpr yet, still think i might have air in my coolant system. idle surges when warm some times. might have to do some tinkering. will post back with mpg numbers
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By suspendedHatch
- Thu Feb 09, 2012 5:32 am #294026 If your tire aspect ratio is different than stock it will throw off your mpg calculations.

Most common causes of bad fuel economy are poor choice of engine mods, bad or improperly inflated tires, O2 sensor, or some other problem putting the ECU in limp mode. Does your exhaust output black smoke (stains on your rear bumper)? Did you make any change to the injectors or fpr? Do you have a chipped ECU?

Have you checked the ignition timing?
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By -paul
- Thu Feb 09, 2012 8:47 pm #294145 Just out of curiosity, when indeed black smokes does come from the exhaust and leave black stains, what would that normally indicate? My old D used to leave black stains over my bumper but no visible smoke so to speak.

Apologies for thread take over. Almost related :)
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By FG2_Andrew
- Thu Feb 09, 2012 9:18 pm #294152 blue smoke - oil
white smoke - coolant
black smoke - gas
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