o2 sensor in off-road pipe

[AK83]

This will be a dumb question but I searched and couldn't find a answer. As you already know the factory H-pipe has three total o2 sensors, one on the driver and two on the passenger. I have a off-road H-pipe and there is only one opening for a o2 sensor on the passenger side, does it matter which o2 sensor I connect?

I have the downstream (rear) o2 connected since the upstream (front) o2 sensor can't reach the hole and run a bama tune that I told them will use a offroad pipe but still get a P0135 check engine light keeps coming on.

Thanks.

 

[skwerl]

The front O2 sensors must be connected. The driver's side is in the exhaust manifold and the passenger side needs to be as close to the manifold as possible. The rear O2 sensors are for emissions and are turned off in the tune when using an off road pipe.

 

[AK83]

Shit, I've been driving with the front o2 sensor disconnected, did I harm anything?

 

[AK83]

Nevermind, found my own answer, without the o2 it's going to run rich and retard timing to be on the safe side. I bought o2 extensions from American Muscle so I can connect the front o2, thanks for the help Skwerl.

 

[BadHabit2Break]

Nevermind, found my own answer, without the o2 it's going to run rich and retard timing to be on the safe side. I bought o2 extensions from American Muscle so I can connect the front o2, thanks for the help Skwerl.

Did you throw a CEL?

Sent from my Ironman suit using Jarvis

 

[AK83]

Did you throw a CEL?

Sent from my Ironman suit using Jarvis

Yes it threw a code P0135.


Also why is this moved to chitchat?

 

[BruceH]

Yes it threw a code P0135.


Also why is this moved to chitchat?

You are talking about an o2 sensor location. Chit chat.

 

[AK83]

You are talking about an o2 sensor location. Chit chat.

I was asking about the P0135 code and which connection to use for downstream and upstream and if it'll effect drivability, I already know where the sensor locations are, I even reiterate them in my first post. But I guess the post in general can be classified chitchat, that's fine.

 

[BruceH]

I was asking about the P0135 code and which connection to use for downstream and upstream and if it'll effect drivability, I already know where the sensor locations are, I even reiterate them in my first post. But I guess the post in general can be classified chitchat, that's fine.

I realize it's different than most other forums. Keeping a higher standard on tech helps to keep our tech section technical, lol. In general asking about what to use or where to put things is chit chat. There are exceptions though.

Like previously mentioned the front o2 sensors are the ones used by ecu to adjust fuel trims and they have to be connected so that closed loop can work properly.

 

[AK83]

Like previously mentioned the front o2 sensors are the ones used by ecu to adjust fuel trims and they have to be connected so that closed loop can work properly.

I did a lot of research since, I've found the front o2 sensors are the most important and rear for emissions only which the tune disables, but that even the front o2s are not necessary if the car is tuned properly, that it's to adjust idle and partial throttle air/fuel.

 

[BruceH]

I did a lot of research since, I've found the front o2 sensors are the most important and rear for emissions only which the tune disables, but that even the front o2s are not necessary if the car is tuned properly, that it's to adjust idle and partial throttle air/fuel.

The front o2 sensors adjust the commanded fuel to be at stoich during closed loop. The only time the motor isn't in closed loop is during wot which is open loop. A good tune will only need 5% or so fuel trim either direction so like you say the motor can get by without them if the tune (maf transfer function) is good enough. The ecu will use fuel trim information to adjust the maf transfer function which is a table the ecu uses to predict fuel needs based on airflow. The stock setting is to apply half of the short term correction to the maf transfer function. It's also used for long term fuel trims. They are a prediction of how much to trim the fuel based on averages of the stft (short term fuel trim). These adaptive parameters can cascade to a bad place as the ecu learns bad habits from the bad info.

It sounds like you have the solution figured out. I'm surprised that the orh pipe doesn't have the bung in the same location as stock. Is there any chance that the o2 sensor connections were swapped during the pipe install? It happens.