Should my Cat Smell ??
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26 December 2008, 10:35 AM
#12
If the engine isn't running perfect AFR or has a misfire they can and do smell.
This is why its most noticeable on full throttle and warm up (due to enrichment). If it is happening on a regular basis, I suggest the engine isn't running quite as well as it should be.
This is why its most noticeable on full throttle and warm up (due to enrichment). If it is happening on a regular basis, I suggest the engine isn't running quite as well as it should be.
26 December 2008, 12:21 PM
#13
thats the right answer, cats smell when theres a issue OR they are fooked, the chemical reaction dont actually smell unless theres too much work to do
get the car on a machine, you wanna see hydrocarbons less that 65pcm,,,,,, the legal limit is 200pcm BUT its stupid as anything over 65pcm means theres some sort of issue
my car passed emmisions, even though its not got a cat fitted due to this rule
27 December 2008, 03:41 PM
#17
as i said got get a HC test done ( emissions) and then come back to me with the results,,, then see whos right
btw i sell exhausts for a living and sell afew cats too
27 December 2008, 05:15 PM
#18
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borrowed from the net....
usually if catalictic converter is bad , it will stink like rotten eggs when u drive if you can get under car and shake converter, if it is bad it will rattle. other than that there is no good way to test a catalictic converter
This is the exact opposite of the truth. The rotten egg smell means that the catalytic converter is working properly.
"It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately.
"As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
"Next time Eggbert and Shelley stop behind a vehicle that smells bad, they can be grateful that it's at least not contributing much to atmospheric pollution."
Thanks to this month's Whizard, Dr. Gordon Bartley, a senior research scientist in the Emissions Research Department of the Automotive Products and Emissions Research Division. Bartley specializes in the development, aging, and evaluation of vehicle emission catalysts.
usually if catalictic converter is bad , it will stink like rotten eggs when u drive if you can get under car and shake converter, if it is bad it will rattle. other than that there is no good way to test a catalictic converter
This is the exact opposite of the truth. The rotten egg smell means that the catalytic converter is working properly.
"It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately.
"As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
"Next time Eggbert and Shelley stop behind a vehicle that smells bad, they can be grateful that it's at least not contributing much to atmospheric pollution."
Thanks to this month's Whizard, Dr. Gordon Bartley, a senior research scientist in the Emissions Research Department of the Automotive Products and Emissions Research Division. Bartley specializes in the development, aging, and evaluation of vehicle emission catalysts.
27 December 2008, 06:57 PM
#20
borrowed from the net....
usually if catalictic converter is bad , it will stink like rotten eggs when u drive if you can get under car and shake converter, if it is bad it will rattle. other than that there is no good way to test a catalictic converter
This is the exact opposite of the truth. The rotten egg smell means that the catalytic converter is working properly.
"It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately.
"As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
"Next time Eggbert and Shelley stop behind a vehicle that smells bad, they can be grateful that it's at least not contributing much to atmospheric pollution."
Thanks to this month's Whizard, Dr. Gordon Bartley, a senior research scientist in the Emissions Research Department of the Automotive Products and Emissions Research Division. Bartley specializes in the development, aging, and evaluation of vehicle emission catalysts.
usually if catalictic converter is bad , it will stink like rotten eggs when u drive if you can get under car and shake converter, if it is bad it will rattle. other than that there is no good way to test a catalictic converter
This is the exact opposite of the truth. The rotten egg smell means that the catalytic converter is working properly.
"It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately.
"As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
"Next time Eggbert and Shelley stop behind a vehicle that smells bad, they can be grateful that it's at least not contributing much to atmospheric pollution."
Thanks to this month's Whizard, Dr. Gordon Bartley, a senior research scientist in the Emissions Research Department of the Automotive Products and Emissions Research Division. Bartley specializes in the development, aging, and evaluation of vehicle emission catalysts.
rubbish, cats are made of three metals, paladium, platinum and something else,,, the smell is when theres a problem with the car,,,, and that will then kill the cat,,,,, the cat is a lifetime part in theory but it can be damaged if the fueling aint understood ( mot pass is 200hc, healthy engine is 60hc or below,, meaning that 187 hc is a missfire and will kill the cat, starts with smell)
the internet is full of conflicting info, but cats should NOT smell !!!
27 December 2008, 09:10 PM
#21
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Dont know the answer mate, but if they do smell and its ok, why is it only now you noticed and why doesnt everyones smell, I would think theres something wrong mate.
27 December 2008, 09:58 PM
#22
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so then ginge what qualifys you to say that a dr with probably umpteen degrees in vehicle emissions is wrong!!!
p.s i think the other material is rhodium
p.s i think the other material is rhodium
Last edited by scoobyboy; 27 December 2008 at 10:05 PM.
27 December 2008, 10:45 PM
#23
reason i say hes wrong is,,, well science is all about being right at the time,,,, this bloke with degrees dont sell cats, dont make em and is a scientist with a theory
i sell cats,,,, the company i work for is very well known for exhausts and work very close with alot of other companys aswell
also i was told by B&M who was the first to really look technically into cats and is quite a large company what to look for,,,,, and as said in ALL instances the cars emissions have been over 60hc which shows the engines condition,,,,, if a smelly cat was ever UNDER the 60hc then i would agree but ive yet to see a smelly cat on a car with a low HC,,,,,,,, also the cats job is to convert the HC into nobel gasses to reduce it,,, hence fitting a new car will lower the HC to pass a MOT,,,, but next year will fail again which is why cats always get sent off for testing
a car consists of 2 bricks,,,, take a look at them one day and see the different conditions,,,,,, the first one will either be burnt/melted OR broken up and rattle,,,, also the cat will become purple if the car is lean,,, there the cats that seem to smell the most ive noticed,,,,, but its a sign of a wrecked cat
as said ive delt with alot of cats and looked into this for answers due to a rise in warranty claims, then rejections due to other reasons
28 December 2008, 01:45 AM
#24
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I think we need a bit more info. Does it smell when first started or when hot?
On start up especially on a cold day (and we have had a few recently) before the cat has reached operating temperature the car will be running rich so you can easily have the eggy smell with no problems. If it is doing it when the engine is hot then it could be anything that causes it to run rich such as dirty spark plugs, or getting a bit clogged up, have you done a lot of short slow journeys recently? Or is it due for a service?
some info on cats
Catalytic Converter
On start up especially on a cold day (and we have had a few recently) before the cat has reached operating temperature the car will be running rich so you can easily have the eggy smell with no problems. If it is doing it when the engine is hot then it could be anything that causes it to run rich such as dirty spark plugs, or getting a bit clogged up, have you done a lot of short slow journeys recently? Or is it due for a service?
some info on cats
Catalytic Converter
28 December 2008, 03:05 AM
#25
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I have always been under the impression that all cars, if driven around for miles, making short journeys never getting hot will smell when finaly getting hot or when driven hard, due to the fact that the cat doesn't get hot enough.
Doesn't it take 30mins of steady driving to bring a cat to tempreature before it starts to work effectivly.
Of course it could also be that it is dead, or that the car is over fueling.
Doesn't it take 30mins of steady driving to bring a cat to tempreature before it starts to work effectivly.
Of course it could also be that it is dead, or that the car is over fueling.
28 December 2008, 08:05 AM
#26
the cat dont work till its upto 400 degrees,,,,,, but also the reaction dont work till then either so again there shouldnt be a smell !!!
fit a new cat and the smell vanishes,,, providing the hc goes down to 60hc !!!
fit a new cat and the smell vanishes,,, providing the hc goes down to 60hc !!!
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