Civic EG

How many miles are you all getting to a full tank?? I have a d15, I filled it up and put 260 miles on the odometer and i have an eighth of a tank left.. I know this car has a small tank (11.9 gal) but I figured Id get more miles to full tank than this...also I pulled my spark plugs and the bottom is a bit black, that would mean Im running rich...Im thinking that it is the o2 sensor.... Any other suggestions????

Yea try that first but do u think it is failing ? Whens the last time you changed your spark plugs? That affects mileage as well.

also you said you have an eight of a tank left 20+ mpg aint so bad

breez wrote:also you said you have an eight of a tank left 20+ mpg aint so bad

vx ftmfw.

I changed the spark plugs about 2 or 3 weeks ago....I checked them about 1 week ago and the threads were black, which would indicate that I am getting too much gas (running rich)....the o2 sensor controls you're air/fuel ratio...

"When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. Your car performs poorly and uses more fuel than it needs to." (www.howstuffworks.com)

Im pretty sure this is the problem, but I always like to ask, because there are some things best left to more experienced honda enthusiasts.. as I am new to the game so I like to ask a hundred questions rather than guess and spend money on unnecessary parts or put time into unnecessary labor.

Any advice is always greatly appreciated

understandable. I think the O2 sensor would throw a code not a 100% . Do you have a cel on ?

I get about 430+ kilometers to a tank. Worked out, I havent gotten worse than 29 mpg since I put in my D15b.

Actually Im not throwing any codes, but like I said I am on track to get less than 300 miles to this tank, I know something isn't right. The o2 sensor is the only thing imo that would effect my gas mileage like this..

jrhdominos wrote:Actually Im not throwing any codes, but like I said I am on track to get less than 300 miles to this tank, I know something isn't right. The o2 sensor is the only thing imo that would effect my gas mileage like this..

I ran my parts crx without a o2 sensor and that mug got amazing gas mileage, lol. It was loud as hell but still..

I know this is basically a useless post in your case, but thought I'd share. Carry on.

An o2 sensor can be going bad, but not bad enough to throw a CEL.

jdm_ferio_man was getting bad mileage cause of his timing... i remember him saying the car ran alright but only got 10-11 mpg. found out the timing was off, fixed it, and the mpg's went way up. something to look into

All these are pretty good responses, Ill check into the timing also; but first Im gonna get a new o2 sensor, only 50 dollars, and you gotta replace them anyway, but I will be looking into all this, it could be a few different things

a bad o2 sensor will greatly shorten the life of your catalytic converter as well.
but the biggest factor for mpg is the driver.
my y7 powered ej6 gets the same mpg as my b18b1/auto powered db7

Yea hopefully the cat converter didnt go bad thats another dollar spent but towards a better running honda tho !