06 LGT downstream o2 sensor delete?

I'm a little confused. I have always been under the impression that on cars with a downstream o2 sensor it's strictly to keep an eye on emissions and can be removed if the code is tuned out.

 

But after some research I'm reading that subaru 32bit ecu's use this downstream o2 sensor for more than just cat efficiency......

 

Is this true? I want to remove the rear o2 and put a wideband in it's place.

 

I have a catless DP so am not really sure what purpose the rear o2 would serve anymore.

 

Thanks in advance.

Yes. The downstream O2 sensor adds data that the ECM uses to make finite fueling changes. You should not delete it. You should add another bung for your wideband sensor.

Ok, thanks for the speedy and good answer.

You can disable AF3 correction and learning and remove the rear O2 sensor if you run with no cats. If you do not disable AF3 with tuning, then your car will run rich with no rear O2.

You can disable AF3 correction and learning and remove the rear O2 sensor if you run with no cats. If you do not disable AF3 with tuning, then your car will run rich with no rear O2.

 

 

Hmmmm, very interesting. What would the downside be to this "if any"?

 

Thank you.

No downside. I have run my car with no rear O2 for years with the AF3 disabled in the tune. My wideband likes that location too. It's only needed on a catted car to properly give feedback for the AFR to oscillate to prolong catalyst life.

Thanks Th3Franz, I will ask Bren about disabling the AF3. I'd much rather use the factory wiring that used to goto the rear o2 to hook up my wideband vs running more wires on my car.

 

 

EDIT: Is disabling the AF3 something I can do with my AP easily? I'm really not interested in getting deep into modifications of the map.

You can disable it with access tuner race and just make that change - it's just a couple values you set to 0. Modify the red boxed items and set them to 0.

Thanks Th3Franz, I will ask Bren about disabling the AF3. I'd much rather use the factory wiring that used to goto the rear o2 to hook up my wideband vs running more wires on my car.

 

 

EDIT: Is disabling the AF3 something I can do with my AP easily? I'm really not interested in getting deep into modifications of the map.

 

 

The ECU won't read a WB (0-5v) signal from my understanding, and most WBo2's have some sort of brain/control box that needs to be wired up/in so it's more than just a o2 sensor swap.

 

If you are using ATR on a laptop to datalog, I have a Innovate LC-1 that I wired up to a cigarette lighter plug for full portability so I wouldn't have to actually install a gauge permanently that has worked very well for my application.

 

When it's time to log, I throw the WBo2 into the bung I had welded in (which is on top of the Bellmouth) connect the LC-1 brain to o2 sensor, string the harness out of the hood and into passnger compartment, connect to cig lighter and laptop, then I'm ready to log.

 

ATR only jives with I think (5) different WBo2s, I had a hell of a time finding a new LC-1 myself as the LC-2 replaced the LC-1.

 

I tried to read ALL of the Cobb ATR documents and have most of them printed out if you would like to see them?

I'm in Smokey Point/Arlington, let me know if I might be able to help out or you want to check out, maybe borrow my LC-1.

 

My rear o2 sensor is still intact, btw.

I was having issues running a whole point rich, and it smelled like fuel therefore shitty gas mileage and money going out the window. I realized when I went in and checked my tune I had not disabled the fuel trim adjustments from rear o2 sensor, fixed it the other day and now I am running perfectly at 1 lamda during closed loop fueling.

TheBlackPearl, I have an aem and was going to look into re-purposing the factory wires vs running the AEM harness.

For Open source guys, here is how you fix the AF #3 correction limits:

 

http://www.romraider.com/forum/viewtopic.php?f=25&t=8131

http://www.romraider.com/forum/viewtopic.php?f=25&t=8595