Running rich, threw a code for o2 sensor, are they related?

[Admiral]

My car threw a code on the o2 sensor after I removed the cat and ran with a test pipe for quite some time. I firgured a code would come up, but now even after I instlaled a high flow cat, I still have the check engine light on.

So, I checked the codes, and it turns out the downstream o2 sensor is bad. The codes say the heating element in it is bad, and something else (I forget which). I ordered a new o2 sensor yesterday.

My question is, would this bad o2 sensor (which, again, is AFTER the cat) make my car run rich periodically? It usually runs rich while cruising, after some type of acceleration. I only know it's running rich because my A/F gauge and turbo timer AF gauge show me extremely rich numbers, and I'm NOT WOT- so I'm pretty sure they are accurate.

Would a bad o2 sensor cause this? Do you guys think it will be better if I get the new o2 sensor put in?

 

[1bad92awd]

A new O2 sensor might help. The code your probably getting would be for the o2 sensor since you just increased exhaust size. you will probably need an diganostic comp to shut it off. A new O2 sensor will never hurt, but on the other hand i have never seen a blow O2 sensor to make your car run rich. it actually did the opposite on my old 2g, i ran super lean, the a/f gaue wouldnt go past the 2nd led on the left there, so i would just do the o2 sensor and see if it helps

 

[Staytuned]

The rear O2 is for monitoring the cat performance. I have not used mine in my exhaust system for 3 summers with no problems. It is hooked up but stuck inside my car under the seat. My new wideband has replaced it.

 

[spyderman]

As stated in other replys, the O2 after the cat is for monitoring cat performance. Unless the O2 sensor is threaded directly into the cast iron exhaust manifold close to the exhaust ports in the head, the O2 will not get hot enough to operate correctly. The O2 needs to hit 600 deg. F before it starts to work which is why they need internal heating elements when they are located farther back in the system. If you install a non-heated sensor in either location or the heating element goes bad you will run rich as the ECM thinks the engine is cold so it operated in open loop cycle which is the EFI version of a choke.

Replace the O2 sensor and be careful not to get any oil or thread sealer in the sensor. Disconnect you battery and ground the hot battery lead to discharge the memory in the ECM. Light should go out and engine should run fine.