hey everyone. ok so im in the process of building a custom turbo kit and when i had the exhaust shop remove my front o2 sensor they accidently broke it. well at least i think thats what happened. it looks ok to me, but im getting a check engine light (car is back to stock btw) and the only code that shows is p0031. but it wont tell me what it is.... from what ive read online it has something to do with front heater relay blah blah blah useless. the only thing different is that the o2 sensor has been taken out and thenput back in 9i never ran it without the sensor hooked up) but i think its not working right anymore.

the strange thing is that the car runs totally fine. no problems at all. at first it has some issues... it wouldnt rev up past 5k and was reallly sluggish. but as soon as the cel came on it started to run fine... ? beats me.

anyway what im wondering is what the effects of not having the front sensor are?

Any help would be appreciated.

Thanks
Chris

 

Effect is....car won't run properly. It uses the front O2 sensor for A/F control in closed loop.

The PCM won't know WTF is going on and will default to safe maps...that won't be very fuel efficient or effective

 

that pretty much what i was thinking but the strange thing is my car runs just fine. ive noticed that my fuel mpg has gone down a bit (like it running really rich) but otherwise the car runs fine... ? i find this very strange.

Chris

 

I guess it means the default maps aren't that bad Or maybe the sensor is still working and you have a different problem??

 

i cant see how i would have any other issues. nothing has changed except the o2 sensor. i even still have the factory intake box installed. and the o2 sensor was the only part that i really had any issues with. they said it was really hard to remove.

im hopeing that the factory maps are running rich to be on the safe side. id much rather they defaulted to a rich condition then a lean one.

 

anyone have any technical info on how th efront o2 sensor actually works. and what it really does? id like to understand it a bit more.

thanks

 

I doubt you will have problems with it running too lean The default is to run richer.....than snot !

 

lol yeah thats pretty much what its doing now. im averaging about 15 mpg. and it sucks. and honestly thats the only effects that ive noticed with it thus far. it just seems strange to me that a part that cost $300+ only makes the car run leaner. there has to be more to it, i just cant seem to really find any useful info.

chris

 

Ok well i was just curious as to if this o2 was actually broken or not so i went out ond unplugged it from the connection at the back of the engine.

hey guess what... the car runs totally normal still... weird huh? yep thats what i was thinking to myself, but sure enough i went out and drove it around and it runs great as it has been for the last couple weeks. still have a check engine light on.

im almost debating on why even replace the stupid o2 sensor... car dont seem to mind not having it. and if im running a bit rich because of it, then oh well. id rather too rich then too lean.

chris

 

without the o2 sensor the car will be running rich in the 5500 and less rpm range which is a huge waste of gas, above that it already runs rich.

 

the car wont learn any new trims with it off

 

Running too rich can cause carbon problems right?

Damage the CAT and clog EGR valves and othe emmision componets. Those components have small holes which may get clogged earlier making you not pass emissions.

Expensive to fix that stuff.