silentblackhat

Recently I replaced my Oxygen sensor becsause the check engine light came on and told me it ws the primary sensor. I bought a Denso universal replacement(wired up correctly) and the light hasnt come back in since. I used to be getting 33-35mpg but now after the replacement, i have been getting 27-29 mpg. i was wondering if its the sensor that is causing that to happen? I know its not a huge decline but it is a decline and with the gas prices keep going up, i want to try to get as much as i can for mpg.
What does everyone else get for their mpg?

I also forgot to say that I used injector cleaner and i also put Sea Foam in the power brake line to clean out the engine.... I heard of people using that and it lowered the gas mileage by a little bit since everything is flowing more freely in the injectors


Modified by silentblackhat at 2:27 AM 3/27/2005

Kyles ej1

i get 25+ mpg with ocasional spirited driving. its prob the o2 sensor, buy oem

BatuKing

check the O2 to see if it is Lean biased, if so then yea its running too rich.

silentblackhat

how cna i check is its lean biased?

e jay one

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93ejay1 &raquo;</TD></TR><TR><TD CLASS="quote"> its prob the o2 sensor, buy oem</TD></TR></TABLE>

BatuKing

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by silentblackhat &raquo;</TD></TR><TR><TD CLASS="quote">how cna i check is its lean biased?</TD></TR></TABLE>

go and put a labscope on it and check the voltage fluxuation

VM 2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BatuKing &raquo;</TD></TR><TR><TD CLASS="quote">

go and put a labscope on it and check the voltage fluxuation</TD></TR></TABLE>

More info plz?

silentblackhat

Is there somewhere that i can get a labscope to test it out? How much are they? I know what ur talking about tho(to see the wave form from rich to lean to rich and so on...where it crosses the .45v mark)

BatuKing

You can purchase a labscope for $3K to 10K depending on the unit.

but heres the issue, if you get an O2 sensor a good one should switch between .100volts to .900 volts. A lean biased one will only go from .100 to .500 volts so the ECU still sees its switching but its too low of a voltage from the low to the high. Now people say the ECU sees a lowervoltage so it knows. WEll not all computers know some will only see the rise and fall and nothing else so when the ECU sees the voltage is going up it says ok command lean since we are going rich, then opposite for the fall.

yinlun

When I used my fuel injector cleaners (4 stages) it ended up increasing my mpg. On my stealth I went from 280miles to the tank (18.5g and 16mpg) to 400 miles to the tank (21mpg).

I don't see why it would reduce your gas mileage..

EE_Chris

Aside from being lean-biased, the actual switching speed of the sensor should be taken into account.

A slower responding O2 = richer mixtures. And even though the O2 is new, it still could be slower out of the box than the OEM unit. This is especially true of Bosch O2's.

silentblackhat

I bought a new Denso Universal sensor. I thought Denso was the way to go? I know that the OEMs are made by denso, so how wouldit be much different than an OEM one? I have another universal sensor that i can try to pop in and see how that works, would it be worth doin that? Its the same model as the sensor that is on the car allready. Would the 2nd sensor need to be changed also? the car has 93500 miles on it and the cat sensor is origional

Evo-man@20psi

Good Idea keep those injectors clean. And it could also be your air filter

EGfosho

ya it can be your air filter, it can be your fuel filter( if your fuel filter gets clogged, it will make the car run lein) Check your timing. What year and model is ur civic? I think the 92-95 cx uses a single wire O2. If you have that car, change ur single O2 to four wire. I get 35 - 40mpg on my 92 dx.

BatuKing

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EGfosho &raquo;</TD></TR><TR><TD CLASS="quote">ya it can be your air filter, it can be your fuel filter( if your fuel filter gets clogged, it will make the car run lein) . </TD></TR></TABLE>

if it was your air filter you would be running lean, and I doubt it.

Also if it was your fuel filter then you got problems, most people dont know but the true way of testing if it is your fuel filter is to run the car at WOT, if you have hesitation or any driveablity then yes its your filter but thats like 1 in 10,000 on most modern cars esp honda's

silentblackhat

I was just messing around with my OEM one that i thought was broken and took a lighter to it with my Volt Ohm Meter to see if it gave any voltage at all and it did. i decided since iw as bored, to pop it back into the car to see how it would work out. I was really expecting the CEL to go on but it didnt. Hopefully my MPG will increase. personally i think the denso sensors are good for the 2nd sensor in the cat but not the primary


Modified by silentblackhat at 1:40 AM 4/3/2005