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Check engine light after header install

Dweisman429

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I installed a set of 2M Fab catless long tube headers a while back.
It had a Steeda tune right away.

After a few miles I got the CEL to pop on. I checked the code and it was P2096, which is lean bank.

Contacted tuner and was advised to check for exhaust leak. Sure enough, there was a pretty good leak between the two O2 sensors. I got that patched up and it ran fine without CEL for a while.

A few weeks ago, CEL came on again, this time P0420 and P0430, which is O2 catalyst below performance threshold.

So I installed a set of the O2 sensor extensions. It drove better and mileage increased... untill the CEL came back on once again with the same P0420/0430 codes.

I contact Steeda and they respond...

Matt Henschke (Steeda Tuning)

Aug 7, 9:56 AM EDT

Huh, I have not heard of those code coming back after the defoulers. The codes will not effect the performance at all, if it persists you may just have to clear it occasionally.


I wonder if anyone has had this issue and what they have done to fix it. I definitely don't feel like just resetting the CEL occasionally is something I need to do to have the headers on the car.
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18 Smoke

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I installed a set of 2M Fab catless long tube headers a while back.
It had a Steeda tune right away.

After a few miles I got the CEL to pop on. I checked the code and it was P2096, which is lean bank.

Contacted tuner and was advised to check for exhaust leak. Sure enough, there was a pretty good leak between the two O2 sensors. I got that patched up and it ran fine without CEL for a while.

A few weeks ago, CEL came on again, this time P0420 and P0430, which is O2 catalyst below performance threshold.

So I installed a set of the O2 sensor extensions. It drove better and mileage increased... untill the CEL came back on once again with the same P0420/0430 codes.

I contact Steeda and they respond...

Matt Henschke (Steeda Tuning)

Aug 7, 9:56 AM EDT

Huh, I have not heard of those code coming back after the defoulers. The codes will not effect the performance at all, if it persists you may just have to clear it occasionally.


I wonder if anyone has had this issue and what they have done to fix it. I definitely don't feel like just resetting the CEL occasionally is something I need to do to have the headers on the car.
A friend tried some extensions(defoulers) from Auto Zone and had the same problem. I suggested he try these and it fixed it. These are what I use as well. Good luck!
http://www.bigdaddiesgarage.com/str...m7YTaS5D_KN-29WP07H7KkpDHyexUkFxoCsxkQAvD_BwE
 

Genxer

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Silver Bullitt

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My SLP headers w/ hi-flow cats would throw an O2 code occasionally on my GTO. It seemed to always occur when running the car pretty hard. I was also running a different cam. Never seemed to cause any issues, but finally got tired of it and just turned the sensors off.

I might mention, once I switched to Kooks, I never had the same issue, even on the same tune.
 

Cmitchen53

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My SLP headers w/ hi-flow cats would throw an O2 code occasionally on my GTO. It seemed to always occur when running the car pretty hard. I was also running a different cam. Never seemed to cause any issues, but finally got tired of it and just turned the sensors off.

I might mention, once I switched to Kooks, I never had the same issue, even on the same tune.
So I’m currently on kooks green catted 1 7/8 long tubes. Haven’t gotten it tuned yet. Will a good tune take care of my CEL that recently came on?
 

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FruityJudy

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So I’m currently on kooks green catted 1 7/8 long tubes. Haven’t gotten it tuned yet. Will a good tune take care of my CEL that recently came on?
Most tuners wont/dont mess with O2 sensor functions anymore due to the epa. Get the defoulers
 

GregO

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There are also 90 degree fittings for O2 sensors. I used one on my Honda and it never threw a code, where the defouler threw a CEL after a short time
This is usually the magic that works. Sometimes those 90’s need stainless steel wool packing shoved into the 90 before installing the 02………the restrictor orifice diameter is also critical in achieving no cell rear 02’s.
Test, Test and retest until its right.
 
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Red65

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As far as I know, it will not affect performance. Traditionally the lower O2 sensors are there to measure cat efficiency. iirc the top O2’s are what the tuners actually use and the lowers are just there because legally they can’t just turn them off in the tune.
 

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Therealmattlex

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There are ways to wire in resistors into the circuit to trick the ECU into thinking the cats are there and working correctly. I did this on my 01 mustang years ago when I went catless but before my tune. It's fairly easy to do and effective.
 

GregO

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There are ways to wire in resistors into the circuit to trick the ECU into thinking the cats are there and working correctly. I did this on my 01 mustang years ago when I went catless but before my tune. It's fairly easy to do and effective.
This isn’t an option any longer. 21 years ago yes but unless I’ve missed something the resistor trick won’t work.
 
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