FI High-Flow cats & Check Engine light (SES)
 

So I've been having this CEL for about 4 months now and today I found out that it has to do with my Fast-Intentions High Flow cats.

The DTC was P2A03. This code is for "O2 Sensor Circuit Range/Performance Bank 2 Sensor 1"

P2A00 is also another code that can be triggered if the problem is passenger side cat.

If you have both codes P2A00 and P2A03 present and running aftermarket cats it is possible that your problem may be the same as mines.

During the first 2 months when the light came on I just reset the light and kept track of how long it took before it came back on. Initially the light would stay off for about 300-400 miles before it returned.

I put the car on my lift and inspected for any exhaust leaks. I found a very small exhaust leak on my drivers side HFC due to the gasket where it connects to the factory exhaust manifold.

I'm using these gaskets https://www.z1motorsports.com/exhaus...ts-p-6448.html

Loosened and re-tightened bolts using a impact.

Within the last 2 months the light would return after about 150-200 miles of driving after resetting. I found a Denso (OEM) o2 sensor new for $60 and figured it could be a simple, cheap and quick fix.

After installing the o2 sensor and resetting the light, it re-appeared after 100-150 miles of driving. I continued to put it off until I had time to look at it again and just continued resetting the light and tracking how long it took before it would re-occur.

I noticed in recent weeks it returns after only ~100 miles of driving.

I swapped MAF sensors for both banks to see and the DTC remained the same for B2S1. I than tried Clear Mixture Ratio Self-Learning Control Data by unplugging the MAF for Bank 1 and than letting the car briefly idle and than resetting the light.

No dice, light still came on about 90 miles later.

Finally today I put the car back up on the lift to check for exhaust leaks. I was convinced that the exhaust gasket leak got worse over time. The exhaust gasket leak was still VERY small.

So I took my mirror and checked around the cats. Below are my findings.

Attachment 184121
Attachment 184122
Attachment 184123
Attachment 184124

This is how the passenger side fast-intentions hfc looks

Attachment 184125

So it appears that I may have 1 of 3 options.

1. Remove and find someone to weld it back
2. Go back to stock cats (I still have)
3. Purchase new aftermarket HFCs

I have no explanation as to how the up stream o2 sensor is picking up on a exhaust leak down stream of it. I was even monitoring STFT and LTFT and it didn't indicate a rich or lean mixture.

If someone could explain to me that would be great :biggthumpup:

what about the option of contacting FI and telling them that their product is defective...

Definitely get in touch w/ FI, not having that support bracket (as per the OEM cat mounts) may have been a factor in that cracking issue.

Hopefully FI will make things right, they seem to be a quality oriented company so hopefully it will be handled well.

Hey
 

What did you end up doing? I’m in the exact situation currently.

Why did you keep driving with an upstream O2 code?!
You have an obd scanner, right? Can you see AFR?
Was it showing rich or lean?
Lean, I bet.
And that would account for the extra heat in the cats. That heat is probably what cracked those welds.
I don't think the cracks tripped the code. They are a symptom.
If it was running rich you would be loading up the catalytic matrix...
Do you have high flow intakes or any other mod that might make you run lean? Or an intake leak after the TBs
Bad fuel delivery? Bad pump or dirty injectors
Do you have a tune?