O2 sensor triggered after New Xpipe went in

[W3N]

Hello all,

I recently installed a HFC Xpipe from Active Autowerk paired with Eisenmann Race Muffler. After the installation, I went for a drive and CEL popped up. Apparently it is the o2 sensors and all 4 of them have faulty code. They can be cleared when car is running, but it will come back on every time when start up the car. When starting up, it will first appear as a CEL then turn to service engine soon and on dash shows increased emission. Car is running great and did not notice anything wrong with it. Any solutions for this issue?

[drwankel]

Did you replace the gaskets in between the header and x pipe when you installed it?

[W3N]

Originally Posted by drwankel

Did you replace the gaskets in between the header and x pipe when you installed it?

No I didn't, just swapped the Xpipe directly.

[DrFerry]

Originally Posted by W3N

Hello all, I recently installed a HFC Xpipe from Active Autowerk paired with Eisenmann Race Muffler. After the installation, I went for a drive and CEL popped up. Apparently it is the o2 sensors and all 4 of them have faulty code. They can be cleared when car is running, but it will come back on every time when start up the car. When starting up, it will first appear as a CEL then turn to service engine soon and on dash shows increased emission. Car is running great and did not notice anything wrong with it. Any solutions for this issue?

Read up a little on this topic. The Forum Advanced Search feature is your friend.
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https://www.m3post.com/forums/showthread.php?t=1349257
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The CEL from the O2 codes will need to be addressed via a Tune or coding. See thread above.

[DukeofAlexandria]

Originally Posted by W3N

Hello all,

I recently installed a HFC Xpipe from Active Autowerk paired with Eisenmann Race Muffler. After the installation, I went for a drive and CEL popped up. Apparently it is the o2 sensors and all 4 of them have faulty code. They can be cleared when car is running, but it will come back on every time when start up the car. When starting up, it will first appear as a CEL then turn to service engine soon and on dash shows increased emission. Car is running great and did not notice anything wrong with it. Any solutions for this issue?

Like DrFerry said, you realize you need a tune to use this setup, correct?

-Duke

[W3N]

Originally Posted by DukeofAlexandria

Like DrFerry said, you realize you need a tune to use this setup, correct?

-Duke

Yes I do! Just didn't expect them to pop up this quick with a High Flow Cat Xpipe set up. Besides a tune is needed, will it hurt engine if keep driving?

[DrFerry]

Originally Posted by W3N

Yes I do! Just didn't expect them to pop up this quick with a High Flow Cat Xpipe set up. Besides a tune is needed, will it hurt engine if keep driving?

Not really. It's okay to keep driving it. The car will adapt as needed. See the thread discussion at the link below..
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How many of you are running catless with no tune? https://www.m3post.com/forums/showthread.php?t=656221
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And here:
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https://www.bimmerpost.com/forums/sh...php?p=11460799

[DukeofAlexandria]

Originally Posted by W3N

Yes I do! Just didn't expect them to pop up this quick with a High Flow Cat Xpipe set up. Besides a tune is needed, will it hurt engine if keep driving?

HFCs are NOT standard catalytic converter's.

If it's reading too high (which it should be in this case because the HFCs) the DME is going to try and balance it out and lean you out accordingly if it can.

You might get misfires, predet, rough idling… DrFerry or anyone else chime in here as DME and coding is not my strong suit.

Regardless, I'm still so confused as to who or what you read that would make you think this was a good idea? Dozens, if not over 100 threads about tunes and HFC/test pipes on the forum. Search is your friend!

-Duke

[DrFerry]

Originally Posted by DukeofAlexandria

HFCs are NOT standard catalytic converter's.

If it's reading too high (which it should be in this case because the HFCs) the DME is going to try and balance it out and lean you out accordingly if it can.

You might get misfires, predet, rough idling… DrFerry or anyone else chime in here as DME and coding is not my strong suit.

Regardless, I'm still so confused as to who or what you read that would make you think this was a good idea? Dozens, if not over 100 threads about tunes and HFC/test pipes on the forum. Search is your friend!

-Duke

From the links above opinions vary:
>
"Even the tuners agree that no tune is necessary [sic: if you don't mind the dash CEL] since the engine runs off WB02 full time that target the AFR. Since a tune adds a little power to even a stock car, it will add a little power to a catless car. You can always add one down the road.

The biggest complaint people have is that the CEL will be triggered for primary cat failure based on feedback from the rear 02. Evolve sells a tune that will allow the car to pass OBD2 inspection and keep the CEL off. Others sell tunes that will not pass OBD2 inspection but keep the CEL off. Akra sells a Delete-R that will simply clear the code automatically so the CEL is not triggered. Sometimes you can find a used one from someone who upgraded to a tune."

Hopefully this helps.

[DukeofAlexandria]

Originally Posted by DrFerry

From the links above:
>
"Even the tuners agree that no tune is necessary since the engine runs off WB02 full time that target the AFR. Since a tune adds a little power to even a stock car, it will add a little power to a catless car. You can always add one down the road.

The biggest complaint people have is that the CEL will be triggered for primary cat failure based on feedback from the rear 02. Evolve sells a tune that will allow the car to pass OBD2 inspection and keep the CEL off. Others sell tunes that will not pass OBD2 inspection but keep the CEL off. Akra sells a Delete-R that will simply clear the code automatically so the CEL is not triggered. Sometimes you can find a used one from someone who upgraded to a tune."

Hopefully this helps.

Huh….figured the DME would go a bit more bonkers and not handle it the best but this is relatively mild to say the least.

Sorry to get you to copy/paste from the links you provided Doc, thanks!

-Duke

[lonatic]

Try fab speed cat anti foulers that's what I'm gonna try as well. But I'm going to get a tune soon.

[W Cole]

Originally Posted by DukeofAlexandria

Huh….figured the DME would go a bit more bonkers and not handle it the best but this is relatively mild to say the least.

Sorry to get you to copy/paste from the links you provided Doc, thanks!

-Duke

The precat o2’s are the one the dme uses for “tuning” and the state of these remains the same with or without cats or with high flow since they are before the cats. The post cat o2’s are the ones that see a different reading but they are only there to test for emissions compliance. This is why emissions testing for modern cars just consists of a visual and plugging into the obd since the cars are constantly checking themselves.

[drwankel]

Originally Posted by W3N

No I didn't, just swapped the Xpipe directly.

I would absolutely replace those gaskets. An exhaust leak between the header and x pipe can cause these symptoms.

Mine were very thin last time I had the exhaust off, and I made sure to replace them. You may consider these a one time use part honestly. Replace every time the x pipe is removed.

[W3N]

Originally Posted by drwankel

I would absolutely replace those gaskets. An exhaust leak between the header and x pipe can cause these symptoms.

Mine were very thin last time I had the exhaust off, and I made sure to replace them. You may consider these a one time use part honestly. Replace every time the x pipe is removed.

Thank you for the suggestion, will get the car on the lift tomorrow or Friday to get it checked!

[drwankel]

Originally Posted by W3N

Thank you for the suggestion, will get the car on the lift tomorrow or Friday to get it checked!

I wouldn't even check it. Order the gaskets and replace them. You need to rule this out. The gaskets are cheap.