I picked up an 07 Odyssey EX in December as a new daily and I love it. I was unloading groceries today and noticed the telltale sulfur smell of a cat going bad. My question is, how do you tell which one? Do you replace all 3? The van has 185k on it. Thanks in advance.
If it has multiple 02 sensors you could use a program like torque while hooked to an obd reader to see at which sensor is no longer reading the difference maybe? Im not sure if 1 cat going bad quickly kills the other one's however
I replaced the last one (after the two banks merge) in our 05. It was rattling though so it was easy to tell.
The stink may be an effect, not a cause. If it is working too hard due to a running issue, it may stink.
Sulfur smell isn't a sign if it dying, just getting sulfur poisoning. Unlike metal poisoning (like phosphorus from oil) sulfur can be removed.
This may sound funny, but an Italian tune up will do a great job- what you want is to cycle rich high load with no load and the fuel off. So hard acceleration and a glide to stop. Do that a few times and any sulfur on the cat will burn off.
Jaynen- typically, the second catalyst doesn't get any damage or poisoning. The first one takes all of that, unless it's REALY bad, which is very non typical.
If the first one goes bad and all the pieces end up stuck in the next one in line, won't it kill that one as well?
ProDarwin said:If the first one goes bad and all the pieces end up stuck in the next one in line, won't it kill that one as well?
Maybe, maybe not. But I was talking more poisoning than physical failure. Two of the ways catalyst fail don't really pass to the second- over temp and poisoning. Physical failure- it's more likely that the chunks of ceramic would to damage to the engine than the next cat. Most likely, it would just pile up in front and block things.
In reply to alfadriver :
Thanks for the advice, I did as you suggested and the smell is completely gone now.
Physical failure- it's more likely that the chunks of ceramic would to damage to the engine than the next cat. Most likely, it would just pile up in front and block things.
Elaborate on how it could harm the engine??
jfryjfry said:Physical failure- it's more likely that the chunks of ceramic would to damage to the engine than the next cat. Most likely, it would just pile up in front and block things.Elaborate on how it could harm the engine??
In some instances, there's enough backflow into the open exhaust valve that it will pull in small debris. Backflow is pretty common, since in the intake manifold pressure is commonly below the exhaust manifold, and it's also pretty common that there's valve overlap. Given the geometry of flat engines, where gravity does not just take the particles to the lowest point, it's apparently a common problem in Subaru engines.
Its common in a few cars from the early 2000s. The MRS and Sentra SE-R SpecV are both known to lose engines due to this. They have a cat in the exhaust manifold very close to the ports.
Nissan Altima and Maxima catalyst that were in the manifold would break down and the precious metal dust would get sucked back in to the motor. It would totally wipe out the rings and cylinder walls.
The Odyssey's catalyst monitors would have triggered a code well before any noticeable failure of the cats.
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