O2 sensor has no factory signal (Aust Model)?

OK, here's the story.

I ordered my Yoshi from the US, pipe comes with no bung hole.

We have an O2 sensor here from the factory. I curse a bit and think ho hum, I'll just have to weld it into the Yoshi.
So Im trial fitting it...unplug the O2 sensor, out of curiosity I fire it up....huh? no CEL, no stutter, runs like normal?
I know the factory sensor is only for closed loop idle control but it should throw up an error if its not plugged in??

New Yoshi pipe is installed (minus O2) and running fine, couple of pops but thats life.

Im going to install a PCV and Autotune in the next few weeks anyway but thought it was curious that the brain didnt seem to care that
there was no lambda signal.

Either that or Im now running so lean the engine has literally hours left to live.....

carby wrote:

I know the factory sensor is only for closed loop idle control...

How do you know that?

combo wrote:

carby wrote:

I know the factory sensor is only for closed loop idle control...

How do you know that?

I'll admit, no concrete evidence. Happy to be corrected (its why I posted the question).

But I know its not a wideband sensor and the ECU has no learning capabilites and is therefore an addition by Yamaha for emissions control not for the purpose of remapping the factory programme to accomodate possible fuel/air/exhaust changes by adventurous owners.

c

I guess the question to be asked that will clear this question is if the factory O2 probe is narrow or wide band.

My guess is narrow (cheaper,...only for keeping lambda proper at idle) as opposed to an expensive wideband which would be useless retapping into an aftermarket pipe unless you really wanted lambda at idle.

http://www.ehow.com/facts_7351759_narrow-wide-band-o2-sensor.html

c

you keep saying "you know" and answer all your question, I don't understand your motivation

Quote :

WR250R is equipped with an oxygen sensor in the exhaust which feeds data to the ECU and adjusts fuel/air mix accordingly to ensure more complete combustion.

http://www.fullnoise.com.au/new_products/index.cfm?fuseaction=display_full&product_id=82&Ntitle=New%20Product:%202008%20Yamaha%20WR250R&cfid=13073413&cftoken=47257340&dts=482010980

A bike shop welded a nut into my FMF Q4 pipes for the 02 sensor and it's not running lean, our bikes run great, I think you are wasting a great bit of technoligy getting fuel programers when the 02 sensor works so well

and btw it isn't the pipe making the pops, it's the AIS

That is an interesting press release, chocka with facts, none conclusive if the sensor is wide or narrow band.

"The compact ECU unit receives data from a crank sensor, intake air pressure sensor and throttle position sensor, allowing it to calculate the engine?s optimum fuel volume, intake air volume and injection timing. "

I'd say this comfirms the ECU doesn't use the O2 sensor for fueling, they would note it otherwise.

"For even lower emissions the new WR250R is equipped with an oxygen sensor in the exhaust which feeds data to the ECU and adjusts fuel/air mix accordingly to ensure more complete combustion."

Yamaha marketing speak for 'the idle is clean'.

Happy for someone who has factory proof to chime in here, I would jump for joy if Yamaha had engineered the ECU to learn and adapt to modifications south of the intake however I find this hard to believe.

Use the search function, good luck with it mate