Well, I guess its my turn. Let me get all of the relevant info out there; The codes pulled from the car today are P0422/432-Main Catalyst effeciency below threshold, banks 1 and 2. The car is a 1999 355F1 with 17,000 miles. In July of 2007, the dealer did the following; Replaced 3 catalyst temp ecu's Cats rebuilt at this time as well The mileage at the time of service was 16,164 Any direction and thoughts?
If it was me I would take the cats off and put a Tubi exhaust call it a day. Best of luck with your annoying emission regulator device.
If you are running the stock cats it probably means they they have just about had it. It isn't uncommon for the cats to become completely gutted just from driving the car. What ever ceramic monolith was used in making stock catalytic converters just can't handle the extra heat. Many have gone to Hyperflow cats because they use a metallic catalyst monolith instead of ceramic, plus they free up some back pressure. The metallic cats can handle the heat better. But before you do anything I would put it on a smog machine to see if it passes. Since your car is a '99 it's an OBDII system, meaning you have four O2 sensors, two on each bank, one before the cat and one after. I would imagine that the O2 sensor/s after the cat/s is the one getting the bad reading/s. Now I'm not totally positive on this but, I think (?) that the O2 sensors are the same. So you may want to try swapping the O2 sensors from the front of the cat to the back, and vice versa. Then see if you still get the "below threshold" code. You are checking to make sure that it isn't a problem with your O2 sensors. But then again if there was a problem with the sensors you would have gotten a code for those. Anyway, it's just a thought. Also. On 348's the Mass Air Flow Sensors are supposed to have 383 ohms of resistance. I'm not sure what the resistance is for the '99 355s but it could be the same. Plus you only have 1 MAFS reading the air for both sides of the engine. The reason I'm bringing this up is because, if your MAF is out of spec it could cause the car to run a bit rich and thus cause the cats to over heat. So have a look at the MAF resistance.
Front and rear O2 sensors are not the same. Heater resistance are not the same and exhaust tip are not the same neither. I don't think swapping the sensors is a good idea. It may lead to extra DTC because of heater resistance out of spec. First thing i would do is to look at the rear O2 sensors data, either with an OBD2 reader, or better with an oscilloscope, and compare with the front sensors. If you can see similar signals or data (swapping quickly between 0.1V and 0.9V while the car is idling) that's mean that the rear sensors are doing their job and that your cats are no more working. If the front sensors are OK (swapping quickly between 0.1V and 0.9V while the car is idling) and the rear are stuck, it may be only the rear sensors which failed. Worth to have a look before buying new cats ... There is not such a check or adjustment on 5.2 F355 Mass Air Flow. It is not possible to check the MAF alone. Motronic 5.2 is auto-adaptative and would compensate for a slight out of range of the MAF. Again an OBD2 reader is your friend, have a look to the so called "Long Term Fuel Trim" parameters. If they are significantly different from 0 on both bank, you may have an injection problem (MAF or injectors or fuel pressure, ...)
Based on my recent similar experience the best money you can spend is have the Ferrari diagnosed on an SD2 machine. I used a well known independent here in MA. I am sure there are many competent independents in your area. Expensive to guess, cheaper to confirm!(Can you use cheaper and Ferrari in the same sentence?). Good Luck!
Which dealer? I would contact them. Most FNA dealers (and independants) will stand behind their work for 12 months or 12,000 miles. They can hook it up to the SD2 and find out what is truly going on and if you really need new cats or not. If you do, getting them rebuilt/recored is way less expensive than new $4000 ones from FNA. About $650 each from these guys: http://www.millercat.com/
The dealer was Ferrari of Orange County and I will contact them tomorrow AM. I did purchase the OBD2 reader as I want to educate myself with the car and how it works. The codes listed are what I pulled yesterday.
I learned through experience that the generic OBDII tools are a good rough reference tool but provide limited useful information compared to the Ferrari SD2 diagnostic system. They will not pull Ferrari specific codes or show real time status. My tool showed the Ferrari Cat Overheat code but no information regarding the cause of the problem. The SD2 tool indicated the problem immediately.
There's a recent picture here on Fchat of a 355 owner who wired his Dell PDA to show the real-time data from the Motronic 5.2 while he drove. Looked cool.
Yes, there is a gold diaphram canister a tad larger than a golf ball just below and right of your MAF sensor. It has a short articulation rod to a small lever. Look an see if there is a wire wrapped around holding the 'rod' up.
