05 revup 6MT, with intake, headers, test pipes

Ok, so I bought it like this, and it always threw a code for the bank 1 downstream sensor. I changed the test pipes to resonated test pipes and got longer extensions on the downstream sensors. Now the code for the downstream sensor went away.

A few days later the CEL comes on, P1283 for 02 sensor 1 bank 2. I changed it yesterday. It's a Walker brand from rockauto.

That code went away and now I'm getting P0171, bank 2 lean condition. It's idling rough now, and kind of pinging around 2500rpm. I went over everything I did, made sure there are no leaks (there are no leaks), and also cleaned the MAF sensor.

I dug into my scanner and read some of the sensor data. The bank 2 fuel trim is at 25. Bank 1 is anywhere from 0-10, but mostly around 0.

The voltage on the sensor I just replaced is reading abnormal (I think??). The three other sensors are reading about .28 volts. The one I just replaced is reading 1.2 volts. Is this because of the lean condition? Or maybe a bad sensor?

Anyways I pulled the fuses for the ECU and let it sit a while. I plugged in the scanner and got the data going before I started it. The new sensor was reading 0.6 volts with the ignition on and the car off. The other ones read normal. I started the car and the trims were normal at first and it was idling smoother than ever. Then after a minute or so the new sensor voltage started rising again, to 1.2 volts, and then the rough idle came back. So the ECU reset didn't work.

I have a dyno tune scheduled for the 8th, so I want to get this taken care of beforehand. I've already spoken with them and they said if worse comes to worst, to bring it in the day before the tune and they'll mess with it, but I'd like to avoid that. They also said these things only like Denso or NTK 02 sensors.

Any ideas? I'm out except for maybe throwing the old sensor back in and seeing what it reads on the scanner (maybe it wasn't bad), or trying a different brand.

 

My word of advice is to change it to a NTK O2 sensor ONLY. These cars have been fairly picky with sensors, and it hasn't changed in the 10 years I've owned it.

Sensor #1 on both banks is your wideband and is used for fuel trims. These need to be fully functional for your dyno tune. If the guy is worth anything, he'll see the issue immediately and tell you to come back when it's fixed.

Other than a junk brand on the sensor, there could possibly be a bad gasket at the head to manifold connection. Really only mentioning it since you say the car has headers installed and there's always been some kind of code since you got it.

 

That really depends on the tuner and if they're using your vehicle O2 sensor to read data or if they're clipping an external one onto your exhaust.