i heard if you changed the oxygen sensor it can help gain more MPG...why is that important to change it and its function?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PurpleAccord88 &raquo;</TD></TR><TR><TD CLASS="quote">i heard if you changed the oxygen sensor it can help gain more MPG...why is that important to change it and its function?</TD></TR></TABLE>


if your oxygen sensor is going bad or is bad, the yes you will see an improvement in MPG.

I think it has something to do with how much unburned fuel and air is coming out the exhaust, and adjusts to make it a perfect ratio of 12:1 i want to say.

 

It reads the amount of oxygen in the exhaust and will adjust the air/fuel ratio accordingly by leaning out or adding in more fuel. Obviously if the sensor is reading wrong it's going to affect how much fuel is being used. The sensor may think that there's more oxygen in the exhaust than there is thus using more fuel and lowering your MPG. The reason they go bad is because after a while they get carbon built up on them and just plain wear out from the heat of the exhaust.

 

good explanation A_Rotary_Guy. fyi, when you do change it, do yourself a favor and get the one with the connector already on it. they are a little more expensive but worth the trouble. also, change it yourself. its takes less than 30 if you have the right tools, which is jacks and a wrench set. i think its either a 15mm or a 17mm you have to have.

 

from the FAQ...
http://img254.imageshack.us/im...8.gif

 

Quick side note, Optimal air/fuel ratio is 14:1.

 

wow thanks guy for the info. now where is the oxy senor located....is that the sensor in the middle of the headers. I have a honda accord 98 ex... and also i got a 3inch intake pipe does that affect it also and my mpg
thanks

 

Don't remember for the 6th gen but it will be either on the HEADER or downpipe

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PurpleAccord88 &raquo;</TD></TR><TR><TD CLASS="quote">wow thanks guy for the info. now where is the oxy senor located....is that the sensor in the middle of the headers. I have a honda accord 98 ex... and also i got a 3inch intake pipe does that affect it also and my mpg
thanks</TD></TR></TABLE>

well is ur accord a 4cyl or v6, if its the 4cyl there is one on the header manifold n one on the cat converter, i found mines when i was switchin the headers n exhaust w/ aftermarket n i have a 98 lx 4cyl
but if you have a v6 then i dont kno

 

Just more information for those interested;
You can check if your o2 sensor pretty easy. Buy a back probe for your DMM, look up a wiring diagram and see what color wire is the signal to the ECU. Probe for voltage of that wire AFTER THE CAR IS OUT OF OPEN LOOP. During open loop your computer does not use the oxygen sensor to control the air/fuel ratio but rather uses a pre-programmed richer setting to warm up the car/catalytic converter faster. With the car out of open loop you should be seeing voltages jumping from .1v-.9v. The voltage produced by the O2 sensor is based on the difference of the oxygen outside the o2 sensor, and the oxygen coming out of exhaust. When you have a large difference of air your voltage is higher, when you have a low difference the voltage will be lower. At .1v the computer sees that there is lot of oxygen coming out of exhaust and will leave injectors on for a little bit longer until it reaches around .9v and sees that its getting close to the rich area and will reduce time injectors are open. The process happens really fast, and best seen with an oscilloscope (voltage over time tool). If you hook up your DMM to check for voltages and you're seeing it just stay at a specific voltage without changing or not changing enough your o2 sensor might be faulty. If your car has a second o2 sensor after the cat the voltage for that one will stay around .4v (I believe) I'm sure I put everyone to sleep already so...*walks away*



Modified by 3zFree at 2:36 AM 3/18/2008

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PurpleAccord88 &raquo;</TD></TR><TR><TD CLASS="quote">wow thanks guy for the info. now where is the oxy senor located....is that the sensor in the middle of the headers. I have a honda accord 98 ex... and also i got a 3inch intake pipe does that affect it also and my mpg
thanks</TD></TR></TABLE>

I think the 6th gen is obdII and not obdI. obdII will have two sensors (header and right after the collector on the header) and if is obdI, it will only be after the collector. the are pretty easy to spot though. it will be the only thing plugged into a stock exhaust.

 

Well the thing is that an O2 helps out so ull knw how much the car is edmiting! or sumin. It would help if u got an air to fuel ratio meter for ur car! it will tell u if ur car is running rich or poor but u want to have it at ideal! so check it out at ur local auto parts! k
Pit

 

if u got a obdII Cali sensor which will say under ur hood. you will find 2 sensors. One on the header's down pipe and one on the cat. converter right next to the header's down pipe. I could take a pic if you're not sure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pitcivic &raquo;</TD></TR><TR><TD CLASS="quote">Well the thing is that an O2 helps out so ull knw how much the car is edmiting! or sumin. It would help if u got an air to fuel ratio meter for ur car! it will tell u if ur car is running rich or poor but u want to have it at ideal! so check it out at ur local auto parts! k
Pit</TD></TR></TABLE>

If you read this thread from the start you would have read that the actual function of the O2 sensor was explained already. I wouldn't waste your money on a narrow band AFR gauge. They are absolutely useless, only good for adding useless moving lights to your dash.

 

yea i think it probl in the headers because theres a sensor look alike thing on the stock header shield. Is it hard to remove?

 

i actually have the 4cyl ex. so its on the headers. Is that the only one i have to change ...? or i change the cat one&gt;?

 

Are you positive your o2 sensor is bad? Don't just throw parts at your car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PurpleAccord88 &raquo;</TD></TR><TR><TD CLASS="quote">yea i think it probl in the headers because theres a sensor look alike thing on the stock header shield. Is it hard to remove?</TD></TR></TABLE>

no jus use a wrench and turn it, some ppl use a ratchet to remove it but i jus use a wrench