O2 sensor questions

[Coup D E'Tat]

Hey, after getting my car back together, I forgot that I left the first O2 sensor unplugged at the connector (it wasn't removed from the O2 housing,) after seeing this, I plugged it back in with the car running.

Before I plugged it back in, I was getting a CEL saying the 2nd O2 sensor was bad, and now, after reconnecting my exhaust (was running open downpipe cut before cat., now running a cutout) I'm getting the code P0125.

There is plenty of coolant, and according to the factory temp. gauge, the car gets/stays warm. I changed the thermostat a few months back, so I doubt that is the problem. The other possible fix as listed in a code handbook is to change the engine's coolant temp. sensor (I believe that's what it was, in the handbook.)

After looking more into it, I read that this code is also sometimes thrown by bad O2 sensors. Now, would the first one be bad since I plugged it back in with the car running? Would the 2nd one be bad for any reason? My car has been down for a little while, and needs inspected, and until I get this figured out, I can't drive it

Thanks in advance.

 

[Coup D E'Tat]

OK, after reading up more, I think I'm going to do the resistor mod, or try the tin foil, to get rid of the 2nd O2 sensor.

Does anyone else have any other suggestions?

 

[ltvarney]

If it's crying about the 2nd o2 because you are bypassing the cat, I'd just run an o2 simulator for the 2nd o2. OBDII will cry about the 2nd o2 all day long when the cat is bypassed. This is what I see for your code:

P0125 Excessive Time to Enter Closed Loop Fuel Control

I'd think it was the 2nd o2 causing the problem.

 

[Coup D E'Tat]

I recently saw that the 2nd "ground wire" had broken.

I put both ground wires back on (well, I used some thick copper wire,) and drove around for maybe a total of 30-40 minutes so far, and it hasn't thrown any codes yet. *crosses fingers*

Now, if I take it to get inspected now, and say the ECU isn't done configuring whatever it configures, will I fail? Basically, will I fail no matter what, or can a shop still pass it, even if all the codes aren't set yet?

Also, when I reconnected my exhaust, and it threw another code, it threw P0125, not the other one that it threw earlier (P0135, I think.) When AutoZone scanned it, it said A) thermostat, which I replaced recently, B) low coolant, and I have plenty, and C) Excessive Time to Enter Closed Loop Fuel Control - I've read that the computer will not go into "closed loop" mode until the O2's reach a certain voltage, so I figured maybe that had something to do with the 2nd O2 sensor, or the lack of ground wires?

Wow, what a long post. Thanks for reading