Aftermarket Wideband to Rear O2 signal

[buddy32]

Originally Posted by Peace@Ptuning

Hi There,

Ken and our tuner are already on this, We should have an answer for you really soon! If you need to find out progress or have any other questions, please contact Ken@ptuning.com

Thank you!

-Peace

Yup! Guys at Ptuning are looking into it as well, could be something as simple as forgetting it on the tune. Just wanted to see how other people have gotten rid of the code. Looks like it's popped up before.

Thanks Peace!!

[wooly35]

I have two bungs on the test pipe and one bung that is plugged on the down pipe... why couldn't I just plug the wideband into the down pipe and not mess with the two stock O2 sensors? Is it to close to the turbo to get an accurate reading?

[buddy32]

Turns out it was just a tune. Everything's good! No more CEL.
@wooly35. The stock O2 sensor has a smaller range of readings than your aftermarket wideband sensor.

[King Tut]

Originally Posted by Peace@Ptuning

Hi There,

Ken and our tuner are already on this, We should have an answer for you really soon! If you need to find out progress or have any other questions, please contact Ken@ptuning.com

Thank you!

-Peace

Hey Ken @ PTUNING. Nice talking to you today. I need those fittings doe.

[Skorov]

Originally Posted by moto-mike

That's correct. Just make sure to disable rear o2 learning and codes as mentioned elsewhere in this thread.

I thought the rear sensor was only used for Cat efficiency checks. Which map controls rear o2 learning?

edit: okay... I found the map to disable rear o2 learning.

A few more questions though. What is that map usually used for?

And, ecutek recommends disabling long term fuel trims when the rear o2 sensor input is repurposed or with FI. Is this a good idea? What's the reasoning behind this?

Thanks! @Sportsguy83 @steve99 @moto-mike

[Sportsguy83]

Originally Posted by Skorov

I thought the rear sensor was only used for Cat efficiency checks. Which map controls rear o2 learning?

edit: okay... I found the map to disable rear o2 learning.

A few more questions though. What is that map usually used for?

And, ecutek recommends disabling long term fuel trims when the rear o2 sensor input is repurposed or with FI. Is this a good idea? What's the reasoning behind this?

Thanks! @Sportsguy83 @steve99 @moto-mike

For your last questions, don't quote me on this and someone can correct me, but I believe the long term fuel trims will affect your open loop fueling, meaning even if you tune the car at one point to be perfectly on target AFR, the LTFT will affect it and you will not be hitting target AFR as time goes.

What map controls the O2 learning?

[Kodename47]

Originally Posted by Sportsguy83

For your last questions, don't quote me on this and someone can correct me, but I believe the long term fuel trims will affect your open loop fueling, meaning even if you tune the car at one point to be perfectly on target AFR, the LTFT will affect it and you will not be hitting target AFR as time goes.

What map controls the O2 learning?

You'd want to change the CL compensation tables to 14.7 (ECUtek) / 0 (Romraider) and then adjust the Rear O2 correction limits and LTFT max/min to 0. That will stop all LTFT I believe.

[Skorov]

Originally Posted by Sportsguy83

For your last questions, don't quote me on this and someone can correct me, but I believe the long term fuel trims will affect your open loop fueling, meaning even if you tune the car at one point to be perfectly on target AFR, the LTFT will affect it and you will not be hitting target AFR as time goes.

What map controls the O2 learning?

That sounds right. But isn't that intended functionality? As in, the LTFT will correct any errors in fueling caused by MAF errors for example. If you remove that functionality then you allowing the error to go uncorrected. I must be missing something...

In EcuTek the map is called "AF Correction #3 Limit - Rear O2 Learning"

Thanks for your help! :-)

[steve99]

Originally Posted by Skorov

That sounds right. But isn't that intended functionality? As in, the LTFT will correct any errors in fueling caused by MAF errors for example. If you remove that functionality then you allowing the error to go uncorrected. I must be missing something...

In EcuTek the map is called "AF Correction #3 Limit - Rear O2 Learning"

Thanks for your help! :-)

front 02 sensor is used for fueling correction and is main 02 sensor, is only o2 needed for engine to run.

rear 02 for cat efficiency checks , and i believe cruise control and cruise fueling corrections. If rear 02 not disabled in rom then Cruise control does not work and you also get cels for secondary o2 heater circuit.
apparently your cruising fuel economy suffers without rear o2 sensor being disabled. due no AF correction #3.

[Skorov]

Originally Posted by steve99

front 02 sensor is used for fueling correction and is main 02 sensor, is only o2 needed for engine to run.

rear 02 for cat efficiency checks , and i believe cruise control and cruise fueling corrections. If rear 02 not disabled in rom then Cruise control does not work and you also get cels for secondary o2 heater circuit.
apparently your cruising fuel economy suffers without rear o2 sensor being disabled. due no AF correction #3.

I see. But functionally, it does not affect the engine, does it?

What about disabling LTFT? Is this common practice or really depends on the tuner?

Thanks!

[steve99]

Originally Posted by Skorov

I see. But functionally, it does not affect the engine, does it?

What about disabling LTFT? Is this common practice or really depends on the tuner?

Thanks!

Yes car will run without rear 02, ecutek can use that ecu input for flex sensor.

As for disabling LTFT, have no experience with that but I believe @Kodename47 has done that with his SC kit

[Skorov]

My install went relatively well! I'm scaling the AFR input now and seeing that I'm getting some conflicting data.

The ECU's AFR reading (front O2 sensor (?)) is showing one thing and the gauge display is showing another. Which should I trust?
Should I scale the AFR input to match the ECU's value or the display's value?

Thanks!

[steve99]

Originally Posted by Skorov

My install went relatively well! I'm scaling the AFR input now and seeing that I'm getting some conflicting data.

The ECU's AFR reading (front O2 sensor (?)) is showing one thing and the gauge display is showing another. Which should I trust?
Should I scale the AFR input to match the ECU's value or the display's value?

Thanks!

I would talk to your tuner

Standard front 02 scaling only reads to about 12 afr at richest which is was ecu "sees"
positioning of your wideband will effect the afr it sees.

[Skorov]

Originally Posted by steve99

I would talk to your tuner

Standard front 02 scaling only reads to about 12 afr at richest which is was ecu "sees"
positioning of your wideband will effect the afr it sees.

I'll try giving him a call today, but he's always busy and rarely answers.

Looking at values between 12 and 16 (where the front O2 reads accurately), there is a constant difference between. The readings should be basically the same since they are positioned less than 30cm apart with no cat between.

It seems like I'm having the same issues as some people in this thread of the output voltage being off by about 0.38V. The current work-around seems to be to just rescale the values, but I will do some tests to see if I can't correct this error to produce the proper maximum voltage of 4.5V.

I'll write back if I manage to find the fix. :-)