I have a 98 355F1 So my check engine light came on, pulled codes and got P0422, main catalyst below efficiency. At first I thought I would swap O2 sensors side to side and see if the code followed. While I was working I decided to just remove the cat and see if anything is visible. I removed it and found a small hole in the center. The hole is about 3/16 or so (guessing) and very close to the center of the matrix. Pretty tough to get a good photo, but clear enough to determine if this is normal. All comments welcome. Thanks Image Unavailable, Please Login Image Unavailable, Please Login
The matrix is a corrugated sheet that is rolled b4 insertion. The hole in the middle is natural any time your roll something up that is not infinitely flexible and thin. A tighter roll would damage the sheet. Rgds, Vincenzo
HA HA HA no not at all. Here is what they look like when they are toast Image Unavailable, Please Login
Interesting, I wonder why Ferrari switched the O2 sensor before the main cat on the 360 to only measure the efficiency of the Pre-cat. Because there is no O2 sensors after the main cat to measure anything.
So I guess the cats are OK judging by the responses so far. The reason I posted this was because I read on F Chat recently that when the cats start to fail there can be a small hole that develops in the center. That small hole can be enough to trigger a check engine light, just like mine. Tonight I am going back to plan "A" I will switch O2 sensors side to side and take it for a drive on Friday. If it sets the light for bank 2, I will know it is the sensor. If it sets the light for the same side again I'll just have to dig a little deeper. Thanks for all the help gentlemen!
Google my (real) name, and ask yourself if I'm "trying to be funny" (Save you the googling: this stuff is what I do for a living) There is exactly ONE and ONE reason only (in reality) for catalyst monitoring. Catalyst monitoring is an "anti-tamper" feature mandated by OBD-II legislation. the thresholds for "catalyst efficiency" are set to a multiple (usually 2 or 2.5x) of new catalyst efficiency - which means you shouldn't reach that level over the (predicted) life of the vehicle - or at least 100,000 miles - on a properly running vehicle. Set so "wide" the function serves exactly ONE purpose. Catalyst presence detection - or - "are the cats there". Note that the manufacturer self-certifies this to the EPA in a ream of paperwork, so we can have situations like some Subarus where even removing the cats will not set a catalyst monitoring fault. On other cars, it is set tighter - but usually the "tightness" is a result of a stupid OEM vehicle calibration engineer. In my work I meet lots of those. Jim
The service manager from Ferrari of Seattle regularly posts here and has stated that the 5.2 Motronic F355s are set very tight, and many times he has seen the Hyperflows set "low catalyst efficiency" codes. He seems to have nothing against the product, just that is doesn't seem to always work with the tight parameters set in the Motronic on the later OBDII 355s.
Jim, Since good fortune allows me to run into an expert, this would be a good opportunity for me to ask some questions. On the 360.. How many drive cycles does it take for the CAT efficiency CEL to be triggered if the Pre-CAT were removed? What voltage differentiation is the DME looking for from the 2nd set of O2 sensors? Can the O2 sensors just hang in the engine bay with the blank cover on the threaded hole if the Pre-Cat where removed to prevent CEL? With the main CAT still in place do you think passing SMOG would be an issue? TIA
On my car, MY2001, for each side the forward sensor is before the precat that is imbedded in the header at the bulge right behind the collector. The rear sensor is in a void between two sets of matrix within the main cat. The forward matrix is smaller, about 2 inches long, and is why the cat has the odd bulge before the main body. So this O2 sensor is seeing the precat as well as part of the main cat. Lou
You should not remove your cats. (I have to say this - it's illegal on a federal level and penalties are not fun if you get caught) If you do, you will illuminate a MIL if you complete two warmup cycles where the ECU actually checks the CAT Monitoring. First will set a "pending" code, second the MIL. "SMOG" differs from state to state. Some states check the OBD Monitors - in which case you are screwed. I cannot say as to the main cats.
I saw some very similar ones being made for a motorcycle. That's not a hole - that's where the mandrel starts the winding of the corrugated material that forms the cat matrix. Once wound, the mandrel is extracted and that split circle is left. What you have looks good so I'd look at the sensors that are causing the code. Rick
on my 01 360 im getting the same code po422 b1 cat efficency below thershold,my cats are new and im now thinking its got to be the precats in the manifold on the passenger side also replaced all 4 my 02s and still got light on
Update Swapped post cat O2 sensors side to side to see if the code would show up on the opposite bank. Took the car out on Father's Day for a ride with my Father in law, then out with my son. Don't know exactly how many kilometers/miles we put on. I will guess about 120 km or 70 miles approximately in total. Check engine light did not come on. In this process so far only one thing has come up. When I removed the bank one cat, the one that triggered the light, I found the O2 sensor was really not that tight. Not finger tight, but it took very little wrench pressure to remove. Here's my question: Could a loose connection between the O2 sensor and the cat trigger a light? If so would the cause be an electrical grounding issue or more likely an exhaust leak? If the cause is considered an exhaust leak at the pre-cat position, would the leak suck air in to the exhaust by a venturi effect? Or blow exhaust out? Thanks again for any and all responses. Gary
sometimes it may take 100 miles or more for the cat monitor run.ck with scanner and see if the cat monitor passed its test.
