Just a quick question about o2 sensors

[LJRuddy]

So I had the 2 bolts that hold the rear header to the y-pipe back out. Before I could take it to a local shop to have it fixed (all be damned if i lay on cold wet asphalt when its 15 degrees out just to tighten 2 bolts) I noticed that the CE light would come on and off during the warm up period. I just figured it was from excess fresh air getting into the exhaust causing the rear sensor to be off. I noticed a steep drop in fuel economy from this. Now that the exhaust is fixed, the CE light does not come on but I am wandering if I need to reset the computer and clear the codes. Once an o2 code is tripped, does the computer always default to the maximum A/F settings even though the CE light is not on anymore and the problem is solved?

 

[ultimatesho]

im unsure if the computer resets itslef automatically or not (im wantin to say it dont but dont take my word for it).....but i would reset it manually just for safe measures

 

[SASHO91]

Pull the codes... then reset it.... it'll will clear the code and wont give you any future frustrations.

But no, it will not stay in that "mode". The reason the CEL came on was because the computer was trying to correct something and could not get it back within "spec". Could have been the "lean" condition on the right bank.. but without the actual codes, you can't be sure.

 

[shoon]

Your o2 sensor was picking up on some of the air getting sucked into your leaking exhaust. Your o2 sensor probably just picked up on the extra air and figured you were running lean; hence the check engine light.

Basically, the PCM will do whatever it can to avoid running lean. If the O2 sensor tells the PCM it's running lean, the PCM will dump more fuel in and try to make the A/F ratio more rich.

You would think running rich would be more perilous to the engine with all that extra fuel.. but actually running lean is what causes damage. When the A/F ratio is too lean, the temperatures soar, to the point where you might start burning valves up.

You should get those codes checked just in case, but the leaking exhaust header will more than likely throw a code.