imported_1sickgsx

Hey guys, I need some help with my 94 4door civic lx 1.5 the car is auto,It is completly stock other than a air intake.I bought the car as a work vehicle and now its really bad on gas.I get around 350 highway k's to a tank.And before any one asks I don't beat on it at all.The engine light was on at first and I got the code to replace the o2 sensor on the manifold,I did that now I am getting code 41 and can't get rid of it.Now correct me if I am wrong but should I not be getting around 500-600 kms to a tank??I also heard the o2 sensor wouldn't cause that drastic of a change in fuel mileage??Any imput from you guys would be great,


thanks

imported_hdave

thats correct, you should be gettign 500-600 hwy km's
sorry but i dont have any other input to your problem

imported_94EG6HB

how about last tune up??

Current mileage??

imported_1sickgsx

It has 220,000 but the guy I bought the car from said The engine was replaced around 190,000 .I replaced the spark plugs and pcv valve about a month ago,The wires look pretty new along with the cap and rotor.I also forgot to mension the car failed etest really bad. The weird thing is that the car runs great and power seems normal.

chris_si98

a bad o2 does affect your gas mileage.

Maybe you have a clogged cat or something or a dirty fuel filter. Many problems could cause low mileage.

imported_wajih1

i wouldnt count on the engine being new, people will say anything to sell there cars.

imported_winner007

Is your o2 sensor new or used? If it's used then it's probably no good. Also change back your stock intake box. U get like 50km more per tank. What did your e-test fail on?

imported_t_dot_SiR

well make sure the intake filter is clean
and how fast do you drive on highways? are you pure highway driving or 50/50
replace your cat too since your failed etest badly before...
get a mech to inspect to engine for any other required tune ups...
even if you're not in 500+ km range... 400-450km should be your goal... i do about 50% city and 50% highway... and i get about 440 on 36-37L... i drive about 70 on city and 120 on highway... and i shift about 3000rpm....

imported_1sickgsx

Thanks for the imput guys, As for the o2 sensor it is a brand new bosh.I drive around 90 to 100 on the highway,and yes it is pure highway driving.And the intake filter I just replaced not too long ago.Is that really true about the aftermarket intake???I had one on my sir and didn't see any difference in gas.I know also that because it is auto it will be a liitle worse on gas than a 5spd.If that cat is clogged shouldn't I see a drop of in power??

imported_1sickgsx

oh yeah the car failed emissions on every possible catagory lol

chris_si98

yes if your cat is clogged you'll feel a lack in power.

Sometimes if your cat is bad you'll smell rotten eggs or an odd smell coming from your tailpipe

94-SI-COUPE

it should'nt be 350 at all mine use to give me about 800 on the hwy.. no jokes it had 300K!!!

civicnation

change cat, test with known working o2 sensor, and do the regular tune up type things (fuel filter, air filter, spark plugs, distributor cap, distributor rotor, pcv, injector cleaner, etc)

imported_Moe_Mentum

If you failed in every category on the E-test then this thing needs a proper tune up and inspection. You should also do what's above including checking the timing, make sure you are using the right grade of oil, tire pressure, excessive weight in the trunk. These can also affect fuel economy.

imported_Jayzen

I have a similar problem - I'm guessing it could be related to the cold air intake... I get 325 to 375k/tank... I might try changing the o2 sensor as its prob been years (or decades)