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http://en.wikipedia.org/wiki/Catalytic_converter

The cat has the ability to store a small amount of O2 during a lean condition to add during a rich condition to help with oxidisation apparently. I didn't know they had the capability of actually storing ot, I thought that thy used the levels of O2 that were in the exhaust gas as it flowed through - the necessary amount of O2 being at, or very near to the stoichiometric ratio.

.......or something like that...... :wink:
 

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maneval69 said:
I understand that you are suggesting that the cat is not getting hot enough.
If temperature was an issue, I would think that the Ceramic coated headers would have less problems than non-coated headers. I have seen no such correlation. Therefore I don’t believe that the temperature is an issue.

Your explanation is a possible cause of the CEL but as far as I can tell it is speculation, as is mine.
I am merely pointing out what one of the things the PCM checks the and a likly explination of why the 0430 and 0420 CELs are tripped. The how stuff works link does not contridict anything I've said. It only further supports what the manual said.


Quote from How stuff works


Here is another passage from the manual. section 25 page 9 (or page 7221)
Maneval,

Ceramics can either be heat conductive or heat insulating. The former would not help maintain high temps in the cat, the latter might, minimally, depending on what it is and how thick it is. However, I have no idea what kind of ceramic coating is on those headers.

I can't for the life of me see where the HSW article bolsters your assertion that O2 is "stored" by the cat. First, a modern cat PRODUCES O2 by taking the NOx (unwanted pollution-causing by-products of the combustion; remember air is 78% N2!) and converting it catalytically to N2 and O2, and it allows the remanent atmospheric O2 that didn't get used in the combustion to pass through to the second stage, which catalyzes the uncombusted hydrocarbons and carbon monoxide (CO) to CO2 and H2O. The O2 molecules momentarily adhere to the catalytic substrate (Pt and Pd) which weakens the O—O bond, allowing the oxygen to more readily react with HC's... but this is a momentary transient state; there's no "storage" going on.

So DESPITE what the service manual says, the cat DOES NOT STORE O2! If the downstream sensor shows the desired LOW O2 reading (high voltage from the sensor), IT'S BECAUSE IT WAS ALL PROPERLY CONVERTED TO CO2 AND H2O! :yes: If the O2 reading is high (low voltage from the sensor), it is interpreted as meaning that there was not enough fuel injected to react with all the incoming O2. The PCM tries to maintain near-perfect stoichiometry: just enough fuel for the amount of air coming in. However, if the cat isn't doing its job, the O2 reading will be too high, even WITH the correct mix of air and fuel.

A properly operating cat needs to be at a substantially elevated temp, and moving it farther from the engine can deleteriously affect its operation by not allowing it to get hot enough.

Please, I'm not trying to belittle you or anyone else, but I want everyone to have correct info! :razz: And I assert that the service manual's description is all wet. Or maybe it's on life-support, in need of oxygen! :wink:

Respectifully,

Tom
 

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My hero..... :D
 

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arfur said:
http://en.wikipedia.org/wiki/Catalytic_converter

The cat has the ability to store a small amount of O2 during a lean condition to add during a rich condition to help with oxidisation apparently. I didn't know they had the capability of actually storing ot, I thought that thy used the levels of O2 that were in the exhaust gas as it flowed through - the necessary amount of O2 being at, or very near to the stoichiometric ratio.

.......or something like that...... :wink:
They're talking very TINY amounts here... from a rev or two of the engine! It's not like some O2 sponge.

One thing I hadn't considered (from the Wikipedia article): "Oxygen sensors only work when at operating temperature, when they output a voltage based on the O2 level in the exhaust gas to the computer. Typically a single wire oxygen sensor will take 3-5 minutes to reach operating temperature. The more expensive heated sensors (3 to 5 wires) can reach operating temperature in 1 minute."

IOW: it's not ONLY be the cat's temp that's important; the sensor's temp is critical, too. Do the O2 sensors have multiple wires going to them? Meaning: are they heated?
 

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arfur said:
My hero..... :D
:shifty: People are watching!:embarrese

:tongue::D
 

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falchulk said:
Where did you get that explanation from? On most cars, it's usually that the 02 diffrence betweeen the 2 sensors is diffrent then stock. Hence the CEL. Never heard of the sensor being too cool.
I wasn't saying the sensor was too cool ,but rather the exhaust flowing over the sensor. A factory setup flows slow causing the gas to spend more time in the cat and retains more heat than A high flow cat which flows faster and retains less heat ...Which is how i came up with the too cool theory...
 

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HemiChemi said:
They're talking very TINY amounts here... from a rev or two of the engine! It's not like some O2 sponge.

One thing I hadn't considered (from the Wikipedia article): "Oxygen sensors only work when at operating temperature, when they output a voltage based on the O2 level in the exhaust gas to the computer. Typically a single wire oxygen sensor will take 3-5 minutes to reach operating temperature. The more expensive heated sensors (3 to 5 wires) can reach operating temperature in 1 minute."

IOW: it's not ONLY be the cat's temp that's important; the sensor's temp is critical, too. Do the O2 sensors have multiple wires going to them? Meaning: are they heated?
How does an O2 sensor work?

An Oxygen sensor is a chemical generator. It is constantly making
a comparison between the Oxygen inside the exhaust manifold and air
outside the engine. If this comparison shows little or no
Oxygen in the exhaust manifold, a voltage is generated. The
output of the sensor is usually between 0 and 1.1 volts. All
spark combustion engines need the proper air fuel ratio to
operate correctly. For gasoline this is 14.7 parts of air to one
part of fuel. When the engine has more fuel than needed, all
available Oxygen is consumed in the cylinder and gasses leaving
through the exhaust contain almost no Oxygen. This sends out a
voltage greater than 0.45 volts. If the engine is running lean,
all fuel is burned, and the extra Oxygen leaves the cylinder and
flows into the exhaust. In this case, the sensor voltage goes
lower than 0.45 volts. Usually the output range seen seen is
0.2 to 0.7 volts.

The sensor does not begin to generate it's full output until it
reaches about 600 degrees F. Prior to this time the sensor is
not conductive. It is as if the circuit between the sensor and
computer is not complete. The mid point is about 0.45 volts.
This is neither rich nor lean. A fully warm O2 sensor *will not
spend any time at 0.45 volts*. In many cars, the computer sends
out a bias voltage of 0.45 through the O2 sensor wire. If the
sensor is not warm, or if the circuit is not complete, the computer
picks up a steady 0.45 volts. Since the computer knows this is
an "illegal" value, it judges the sensor to not be ready. It
remains in open loop operation, and uses all sensors except the
O2 to determine fuel delivery. Any time an engine is operated
in open loop, it runs somewhat rich and makes more exhaust
emissions. This translates into lost power, poor fuel economy
and air pollution.

The O2 sensor is constantly in a state of transition between high
and low voltage. Manfucturers call this crossing of the 0.45
volt mark O2 cross counts. The higher the number of O2 cross
counts, the better the sensor and other parts of the computer
control system are working. It is important to remember that the
O2 sensor is comparing the amount of Oxygen inside and outside
the engine. If the outside of the sensor should become blocked,
or coated with oil, sound insulation, undercoating or antifreeze,
(among other things), this comparison is not possible.

http://www.wps.com/LPG/o2sensor.html


Apprently there are heated and unheated types.....

http://www.parttrackers.com/library/1/24/27/


:D

And I think that the 'storage of oxygen' thing is a little misleading as well - it isn't a sponge - that's true. :)
 

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this is a great debate on the inter working of a cat but does anyone know how to beat the blessed thing..........lmao.

btw - installing my mechanical o2 sim tomorrow to fool something into thinking that something else is working properly so the other thing stops making the something give me cels........:tongue:
 

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GoDaddy said:
this is a great debate on the inter working of a cat but does anyone know how to beat the blessed thing..........lmao.

btw - installing my mechanical o2 sim tomorrow to fool something into thinking that something else is working properly so the other thing stops making the something give me cels........:tongue:
I'd try the spacer things between the thing and the thing first... :tongue: :tongue:
 

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HemiChemi said:
I'd try the spacer things between the thing and the thing first... :tongue: :tongue:
that should work.....<damn chemists....>:tongue:

i just hope this works b/c i am tired of the damn thing making my thingy go limp......:wink:
 

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GoDaddy said:
that should work.....<damn chemists....>:tongue:

i just hope this works b/c i am tired of the damn thing making my thingy go limp......:wink:
Can't have a limp thingy, Mr. Long-tube! What would ppl think? :cool:
 

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HemiChemi said:
Maneval,

Ceramics can either be heat conductive or heat insulating. The former would not help maintain high temps in the cat, the latter might, minimally, depending on what it is and how thick it is. However, I have no idea what kind of ceramic coating is on those headers.

I can't for the life of me see where the HSW article bolsters your assertion that O2 is "stored" by the cat. First, a modern cat PRODUCES O2 by taking the NOx (unwanted pollution-causing by-products of the combustion; remember air is 78% N2!) and converting it catalytically to N2 and O2, and it allows the remanent atmospheric O2 that didn't get used in the combustion to pass through to the second stage, which catalyzes the uncombusted hydrocarbons and carbon monoxide (CO) to CO2 and H2O. The O2 molecules momentarily adhere to the catalytic substrate (Pt and Pd) which weakens the O—O bond, allowing the oxygen to more readily react with HC's... but this is a momentary transient state; there's no "storage" going on.

So DESPITE what the service manual says, the cat DOES NOT STORE O2! If the downstream sensor shows the desired LOW O2 reading (high voltage from the sensor), IT'S BECAUSE IT WAS ALL PROPERLY CONVERTED TO CO2 AND H2O! :yes: If the O2 reading is high (low voltage from the sensor), it is interpreted as meaning that there was not enough fuel injected to react with all the incoming O2. The PCM tries to maintain near-perfect stoichiometry: just enough fuel for the amount of air coming in. However, if the cat isn't doing its job, the O2 reading will be too high, even WITH the correct mix of air and fuel.

A properly operating cat needs to be at a substantially elevated temp, and moving it farther from the engine can deleteriously affect its operation by not allowing it to get hot enough.

Please, I'm not trying to belittle you or anyone else, but I want everyone to have correct info! :razz: And I assert that the service manual's description is all wet. Or maybe it's on life-support, in need of oxygen! :wink:

Respectifully,

Tom

The ceramic coating on the headers is intended to contain the heat to improve flow.
I am just arguing to understand, you could very well be right. But at this point I will trust the manual over you, and I do not mean any disrespect by that. I fully expect you feel the same way about what I am saying. (I'm just looking for the answers)
The HSW article does not say where the oxygen comes from.
The Oxidization Catalyst
The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas. For example:
2CO + O2 => 2CO2
But where did this oxygen come from?
The sentence in red is in the article, I did not add it. The article never elaborated.

I don’t see how anything I’ve said disputes anything you’ve said except about the cat storing oxygen.

Also, I am not saying that the cat stores oxygen as part of its normal operation. I think what the manual is saying is that in test mode the PCM leans the mix to above the stoichiometric mix. When this happens the cat is CHARGED with oxygen (that may be a better way to say it) then when the PCM makes the mix richer than stoichiometric the Oxygen Charge is depleted. The rate it depletes is how the PCM calculates the cats efficiency.
????
PS
I hope I'm not coming of as disrespectful,
I have learned more about the science of cars by coming up with a theory having to defend it. If I'm wrong I would rather know about it than continue on in error.
I do want to know if I'm right or wrong.
 

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GoDaddy said:
this is a great debate on the inter working of a cat but does anyone know how to beat the blessed thing..........lmao.

btw - installing my mechanical o2 sim tomorrow to fool something into thinking that something else is working properly so the other thing stops making the something give me cels........:tongue:
Best damn technical explanation yet!! LOL

If I was a girl, I would want kids with you!!!! :D
 

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HemiChemi said:
Can't have a limp thingy, Mr. Long-tube! What would ppl think? :cool:
You're all gwad damn genius' (genii?)

I'm gonna call this the Gump thread! :tongue: :wink:
 

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spend the twenty and buy the mechanical sims and end the thread and then start a thread titled dont delete this thread and it will go on forever and ever and you can get eight million posts. just my two cents.
 

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cip5150 said:
spend the twenty and buy the mechanical sims and end the thread and then start a thread titled dont delete this thread and it will go on forever and ever and you can get eight million posts. just my two cents.
You have 'thread envy' don't you!! :tongue: :)
 

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five thousand and four hundred and something to go!
 

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cip5150 said:
spend the twenty and buy the mechanical sims and end the thread and then start a thread titled dont delete this thread and it will go on forever and ever and you can get eight million posts. just my two cents.
Save $15 and buy them at Autozone - HELP! brand- PN 42009, 18mm sparkplug non-fouler. These are the exact same parts but who ever is selling them (on ebay) is drilling them for you. They are very easy to drill.
Oops, I think I already posted this.
 

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ok peeps....lol....sorry. traded one code for another.....i got the p2096 - post catalyst fuel trim system too lean bank 1.

i put the o2 mechanical sims on sunday and got rid of the 420 and 430 and now i have this one...i wonder if i am backed too far out of the exhaust stream using both of the foulers in conjunction with each other.....

any thoughts.....

my next bet is to take one of the spacers off and just go with a one only spacer....

anyone, bueller, bueller.......lol
 

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GoDaddy said:
ok peeps....lol....sorry. traded one code for another.....i got the p2096 - post catalyst fuel trim system too lean bank 1.

i put the o2 mechanical sims on sunday and got rid of the 420 and 430 and now i have this one...i wonder if i am backed too far out of the exhaust stream using both of the foulers in conjunction with each other.....

any thoughts.....

my next bet is to take one of the spacers off and just go with a one only spacer....

anyone, bueller, bueller.......lol
godaddy, never even heard of anyone getting that code. did you make sure you didnt get any antiseize on the sensors? just a thought.
 
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