Do i still need my O2 censor??
 

hey guys,

I just got my car back from Rotary Performance with a new mazda reman. they told me that i had a brooken O2 censor. From what i gather the O2 is for emissons purposes, and my car is a non-sequential and has all emissions equipment removed. i called mazda today and they want to rape me out of $220 for a new one, and i dont want to get one if i dont need one. can i please get your opinions on this matter PLEASE!

thanks alot!

o2 is for air to fuel ratio. it will be impoissable to tune without this. and think it tells how much gas fumes are in the exhaust.

I belive the o2 sensor is needed to read the exhaust mix and then send a signal to the ecu to adjust the air/fuel ratio on a normal car. Its around 50 bucks. On your car no guess...

here is a better explanation.

Oxygen sensors, or O2 sensors, are required to perform a critical function on your vehicle in the harshest of environments: Measuring the oxygen content of the exhaust just after it leaves the (cylinders) or rotors. The oxygen sensor has to accurately check this red-hot exhaust hundreds of times per minute and send that data to the vehicle computer. The fuel/air mixture hangs in the balance, and you're probably familiar with the symptoms of a bad oxygen sensor: Black smoke from the exhaust, a rotten-egg odor, and poor performance and fuel mileage.

^^are you still running oem ecu?? if so you should replace it, the oem ecu runs in closed loop for cruise and other areas and without it the ecu has to read off of the base map wich will most likely = very rich....I've used the $20 bosch uni. without problems.

bryant, I really hope your not trying to tune your car with the cheazy narrowband o2

hey thanks for all the replys guys. i am running the power fc right now, so will theO2 censor still do the air/fuel mixing, or is that in the hands of the power fc now?

You can disconect the o2 sensor if you want in your FD. All the o2 sensor does on our cars is give us better milage when cuiseing. You can go to your local parts store and get a universal one for about 60 dollars. They do need to be spliced in though, it just takes a second to do so.

Its actually in your hands since you have to controll the PFC. It still does read the o2 when its warm.

[QUOTE=sereneseven
bryant, I really hope your not trying to tune your car with the cheazy narrowband o2[/QUOTE]

no im not.

ask whoever tunned your car if they turned off the o2 feedback....most likely they did

is there a way i can check this out myself?

do you have the commander? if so than yes.

...I havent used mine in forever so my memory is a little shady....

under either setting's or etc. there should be a setting page with ign feedback,o2 feedback, seq. turbo and one other...anyways check there and see....its going to be in jap mumbojumbo... if you can't figure it out I'm sure some one else can chime in with a better memory than me.

just thought of it I believe the page is called "Function select"

This is the simplest answer with your ecu in mind.

No, you do not need it. Period.

Without an o2 sensor, your car will always be in open loop/base timing. This means your ECU will think your car is not warmed up, and you will have a very rich condition. You need to have a switching o2 signal to the ECU to be in closed loop.

I've never used a PFC so I can't say specifically about your situation.

O2 sensors only sense oxygen in your exhaust stream, hence the name, o2 sensor. Less oxygen = rich, more oxygen = lean.

If you can't find a cheaper o2 sensor, then check rx7store.net. They have a Bosch wide-band o2 for $80. You can also get the AEM wide-band and A/F gauge for 300.

Or you can get a $20 universal Bosch O2 sensor, single wire version. And it's pretty easy to install.

SENSOR for God's sake!

And the Bosch ones work just fine.

I replaced mine with a bosch-universal and it was around ~25 bucks..

It helped and I have a PFC...

i just got one of those bosch sensors, just to make sure everything is working good. thanks for all the help!

It's VERY important to keep your censor working... if the Mazda were to slip up & drop the F-bomb on live television... you will be heavily fined!

On a very similar note and possibly something 93rx74lyfe might want to consider if possible...

Could one replace the stock O2 Sensor with a WideBand O2 Sensor? Would this cause any ill effects to the PFC? I know the PFC has a Aux Inputs, of which you can plug the Wideband on, but is there any harm in using the stock O2 location and connections with a wideband?

Everyone who is suggesting wide bands as a replacement of the stock o2 needs to do some homework on what a wide band is, they should also research a little and try to understand the basic concepts of closed loop operaton via pfc/oem.

the short end of it is NO you cannot replace the oem O2 with a wide band and simply plug it in. there is also zero benefit of using a wideband for the sole purpose of retaining the closed loop operation of the PFC/OEM ecu. you can on some WB controller's set-up a NB output to fill in the roll of a NB sensor to retain Closed loop operation.

The PFC does not have aux inputs so if someone wanted to use a WB they would need to add the FC Datalogit.

Sorry you are right the PFC does not, it's the Datalogit... Which is why I was asking about using the Widebad in place of the Stock O2 sensor in the stock location with stock connections... so it's hooked up directly to the PFC.

True, I don't really understand the concept behind the close loop opperation via the PFC/OEM ECU. Which is why I asked the question. Sorry I should have done some research before asking...

sorry im having a little trouble understanding, will the bosch O2 sensor cause bad effects with my PFC or will it work out. or im kinda getting that your saying with the PFC i dont need one at all. sorry for the confusion im just a little lost. :wallbash:

closed loop operation is a mode of fuel metering in which the PFC will read off of a fuel map and also read off of the NB o2 sensor and depending on if the the o2 reads rich or lean the PFC will either add or subtract a set amount fuel in order to maintain a preset definition of stoiche....

You can turn off this operation in the PFC and most tuners when they tune your car do this so that they don't have to worry about the PFC making unwanted changes to the fuelling....if this has been done (car tuned without closed loop) than you don't need the oem o2 anymore But I would reccommend that you invest in a WB set-up so you can mannually monitor your cars tune.

Some Tunners tune the car with Closed Loop in mind and therfore leave this function inabled if this is the case than you should retain the O2, the universal bosch NB O2 that you can get at any parts store for around $20 bucks will work just fine.

this is why I told you to ask your tunner if they used the closed loop function.

If your tuner did a RECALC, which is pretty common, O2 feedback won't work unless they restored/fixed the idle/cruise portion of the map (N01-N06 and P01-P06). That's why they usually disable it, because the engine won't idle correctly otherwise.