Installed catless UEL BORLA headers, got a CEL that you wouldn't expect (NOT P0420) - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

noonedoesnt · 09-04-2017, 08:39 PM

Hi guys, last friday I installed BORLA UEL catless headers, and got a CEL light 2 days later, code P0171, for 'running lean'.

There are MANY others using the same tune im running (A stage 2 UEL catless tune, with delayed low load ignition for pops/bangs out exhaust).

However, i'm pretty sure I have a leak from the passenger side (AUDM) header gasket (which sounds a bit like a puff/ticking sound).

My question is, would I have gotten this CEL code due to having this leak?

Cheers

Apoc · 09-04-2017, 11:13 PM

Yes the CEL is likely related to the exhaust leak. The front sensor is seeing higher O2 than expected (AFR) and has maxed out LTFT. Once the ECU can't adjust fuel trims any further it will throw that code. You may also notice that the exhaust is actually smelling super rich.

noonedoesnt · 09-04-2017, 11:21 PM

Quote:

Originally Posted by Apoc

Yes the CEL is likely related to the exhaust leak. The front sensor is seeing higher A/F ratios and has maxed out LTFT. Once the ECU can't compensate AFR any longer it will throw that code. You may also notice that the exhaust is actually smelling super rich.

I just checked it out, and here is the result:

[ame="https://www.youtube.com/watch?v=bSF9nc62WuE"]Leak1 - YouTube[/ame]

Part in the video is show in this pic:

https://image.ibb.co/nqUvwv/header.png

noonedoesnt · 09-05-2017, 09:24 PM

bump

mav1178 · 09-05-2017, 09:40 PM

Quote:

Originally Posted by noonedoesnt

bump

Quote:

Originally Posted by Apoc

Yes the CEL is likely related to the exhaust leak. The front sensor is seeing higher O2 than expected (AFR) and has maxed out LTFT. Once the ECU can't adjust fuel trims any further it will throw that code. You may also notice that the exhaust is actually smelling super rich.

Dude, the answer was already given to you.

Do you want more people to confirm? If yes, please reply with the number of replies you want to get so we can answer your question definitively.

noonedoesnt · 09-05-2017, 09:43 PM

Quote:

Originally Posted by mav1178

Dude, the answer was already given to you.

Do you want more people to confirm? If yes, please reply with the number of replies you want to get so we can answer your question definitively.

Yes I would like some more people to confirm, that was the purpose of the bump. Maybe someone else has had the same experience.

mav1178 · 09-05-2017, 10:04 PM

Quote:

Originally Posted by noonedoesnt

Yes I would like some more people to confirm, that was the purpose of the bump. Maybe someone else has had the same experience.

https://www.google.com/search?q=p0171+code

You already confirmed you have a leaking header so it's really up to you if you want to accept the diagnosis and fix it, or leave it as-is while you wait for internet keyboard warriors to confirm or not.

But if you want to build up your confirm karma points, my answer is yes.

Pointmutation · 09-05-2017, 10:08 PM

Quote:

Originally Posted by noonedoesnt

bump

Bump for what? Did you fix the leak yet? You still have the code after the leak got fixed?

Tor · 09-05-2017, 10:13 PM

Did you use new gaskets? Did you tighten the nuts with a torque wrench with the correct torque?

Get off the internet and go fix your exhaust leak.

noonedoesnt · 09-05-2017, 10:14 PM

Quote:

Originally Posted by Tor

Did you use new gaskets? Did you tighten the nuts with a torque wrench with the correct torque?

Get off the internet and go fix your exhaust leak.

I will do lol. Just wanted some more confirmation in the meantime, as I can't fix it for a few days.

mav1178 · 09-05-2017, 10:25 PM

Bump for updates.

x808drifter · 09-05-2017, 10:29 PM

Got same code, ignored it.
Car now has AIDS.

guybo · 09-06-2017, 10:28 PM

Quote:

Originally Posted by noonedoesnt

However, i'm pretty sure I have a leak from the passenger side (AUDM) header gasket (which sounds a bit like a puff/ticking sound).

My question is, would I have gotten this CEL code due to having this leak?

Cheers

Yes

noonedoesnt · 09-06-2017, 11:55 PM

Ok tried tightening that nut, but its very hard to access, managed maybe a quarter turn of tightening with a spanner, and the leak sounds like it halved in loudness.

Any downsides to using gasket sealant to finish off?

09-04-2017, 08:39 PM	#1
noonedoesnt Member Join Date: Aug 2017 Drives: 2016 Toyota 86 GTS - Manual Location: Sydney, Australia Posts: 15 Thanks: 0 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Installed catless UEL BORLA headers, got a CEL that you wouldn't expect (NOT P0420) Hi guys, last friday I installed BORLA UEL catless headers, and got a CEL light 2 days later, code P0171, for 'running lean'. There are MANY others using the same tune im running (A stage 2 UEL catless tune, with delayed low load ignition for pops/bangs out exhaust). However, i'm pretty sure I have a leak from the passenger side (AUDM) header gasket (which sounds a bit like a puff/ticking sound). My question is, would I have gotten this CEL code due to having this leak? Cheers

09-04-2017, 11:13 PM	#2
Apoc Senior Member Join Date: Jul 2012 Drives: Raven FR-S 6M Location: Calgary, Canada Posts: 638 Thanks: 348 Thanked 375 Times in 232 Posts Mentioned: 3 Post(s) Tagged: 1 Thread(s)	Yes the CEL is likely related to the exhaust leak. The front sensor is seeing higher O2 than expected (AFR) and has maxed out LTFT. Once the ECU can't adjust fuel trims any further it will throw that code. You may also notice that the exhaust is actually smelling super rich. __________________ “The World is Flat” [\|\|•]=(86)=[•\|\|] Last edited by Apoc; 09-04-2017 at 11:30 PM.

09-05-2017, 10:13 PM	#9
Tor Senior Member Join Date: Feb 2015 Drives: Toyota GT86 Location: Europe Posts: 919 Thanks: 369 Thanked 557 Times in 301 Posts Mentioned: 40 Post(s) Tagged: 2 Thread(s)	Did you use new gaskets? Did you tighten the nuts with a torque wrench with the correct torque? Get off the internet and go fix your exhaust leak. __________________ Build: T(h)or's GT86 hammer (Europe) - essential track setup Youtube: GT86 dude

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09-05-2017, 09:24 PM	#4
noonedoesnt Member Join Date: Aug 2017 Drives: 2016 Toyota 86 GTS - Manual Location: Sydney, Australia Posts: 15 Thanks: 0 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	bump

09-05-2017, 10:25 PM	#11
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09-05-2017, 10:29 PM	#12
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09-06-2017, 11:55 PM	#14
noonedoesnt Member Join Date: Aug 2017 Drives: 2016 Toyota 86 GTS - Manual Location: Sydney, Australia Posts: 15 Thanks: 0 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Ok tried tightening that nut, but its very hard to access, managed maybe a quarter turn of tightening with a spanner, and the leak sounds like it halved in loudness. Any downsides to using gasket sealant to finish off?

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