P0421 / P0431 Trouble Codes (Catalytic Converter) ... anyone have good fix?

There are many conditions that may trigger the Check Engine Light (CEL). And many are spurious or relatively insignificant. But some are significant that without attention paid can lead to costly repairs or pose a safety issue. Although it may be humorous to suggest covering the light so you can better ignore it, I think it is better advice to understand the reason and take action to prevent its occurrence.

 

Went for a drive today ... about 75 miles with the Big Daddies Garage mini-cats installed. Recall that these mini-cats also act as O2 extenders as well.

No Check Engine Light. The distance may not be enough to have a high degree of assurance that I will not get a CEL, but still keeping my fingers crossed.

Steve

 

I had all adaptive parameters reset a week ago ... but it was before I installed the mini-cats. If the codes come back, I will do a full reset again ... i.e., overnight battery off.

Steve

 

I have considered an ECU tune. Am I correct that the ECU tune ignores the codes and therefore suppresses the Check Engine Light? I am concerned that the codes would still be present and the vehicle may not pass emissions testing.

Steve

 

Since installing the Big Daddies Garage mini-cats, I have not had the CEL come back. I do not have 100% confidence that the problem is solved as I do not believe I have put enough miles on the car to repeat the conditions where it did appear before. I need to go for a continuous drive of at least 1 to 2 hours before I can have better confidence. I will keep you updated.

Steve

 

On Feb 17, I installed the Big Daddies Garage Mini-cats. Had all adaptive parameters cleared using an SD2 diagnostic tester. I had posted earlier that I ordered two mini-cats and two 90 degree adapters. The 90-degree adapters cannot be easily threaded into the catalytic converter without dropping the exaust, so I installed the mini-cats without the 90-degree adapter. See post #95 https://www.ferrarichat.com/forum/threads/p0421-p0431-trouble-codes-catalytic-converter-anyone-have-good-fix.552866/page-4#post-145825349

Fast forward to present ... No more codes. I have driven car many times ... mostly short trips with two trips of 75 and about 100 miles each. My configuration:

• 2004 Ferrari 360 Modena
• Fabspeed headers without pre-cats. Headers are wrapped.
• Stock Ferrari catalytic converters
• Big Daddies Garage mini-cats
• Ferrari racing exhaust

Some months ago I purchased a pair of Fabspeed mini-cats, but I sold them. I installed those mini-cats along with a cat-delete pipe, but the codes re-appeared. I decided to re-install the stock cats because the cat-delete pipe made everything much too loud for me. I thought that I would not need the Fabspeed mini-cats because the stock cats were re-installed. I sold them. But a month or so later, the codes came back. The stock headers were likely the contributing factor. I decided to purchase new mini-cats. I got Big Daddies mini cats and 90-degree extenders.

I believe the Big Daddies Garage mini cats are every bit the equal to Fabspeed's and much lower cost. Here is visual comparison:

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The Fabspeed mini-cat is about twice the size / weight of the Big Daddies mini-cat.

My experience is that you do not need the 90-degree (or the 0-degree) extender. I installed Big Daddies mini-cat directly on the Ferrari catalytic converter and seems to fit and work fine. Besides, unless you are willing to drop the exhaust on the 360, you won't be able to install the extenders. The Fabspeed mini-cat comes with a right angle adapter, but the mini-cat itself is about the same distance outside the exhaust stream as Big Daddies' mini-cat.

One thing I did not try ... Big Daddies has a straight stainless steel O2 extender for $15 each. If you do a search, you can find many of these for $10 to $20 each. Maybe even less. It might be worth a try to install the plain vanilla extender first. I saw on Amazon you can get an extender kit where you can piece together the parts to try different extension lengths. ... https://www.amazon.com/Degree-Angled-Engine-Exhaust-Extension/dp/B00B1U6I54/ref=pd_lpo_vtph_263_bs_img_1?_encoding=UTF8&psc=1&refRID=5W57D036P2JKJR8VQQ41

OK. Long story made short ... The Big Daddies mini-cats seem to have resolved the issue of getting the P0421 and P0431 codes. I will update if they come back.

Steve