Its the catalytic converter, stupid

When I say stupid, I am refering to myself.

I have a 1998 3.9L V6 Dakota with 60K miles.
The engine has always been prone to knocking. Its
worse in the summer (hot) and I must always use
mid grade gas (87 octane).

This summer the knocking got real bad. I could
not buy a high enough octane and the temperature
did not seem to matter. So I asked around, posted
on this group and did a web search. There was
a lot of discussion about trying a cooler plug,
or a lower temp thermostat. Even re-rounting the
plug wires. But the bottom line was there is no
magic bullet. This engine knocks.

So I assumed the engine was just getting old. After
all the power seemed to be falling off too. I tried to
put it out of my mind.

Last week I noticed a rattle under the truck.
Got under and found the catalytic converter
had a mass in it that was rattling around. So
I had a new one put in. What a difference. Its
like a new truck. The knocking has stopped. And
the power is back.

Looks like the converter was pluged for most of the
summer and I did not know it. Glad it finally started
rattling.

Live and learn.

 

Where I live we punch them internally and put them back.

 

Thats great news,

hope the feds knock on your door!

 

Thats great!!! Im sure your kids will appreciate that in the yrs to
come..Dont forget , we didnt inherit this earth from our ansestors. we are
borrowing it from our kids
Glenn Beasley
Chrysler Tech

 

Auto emissions are only long term in terms of carbon dioxide. Carbon
monoxide, and hydrocarbons are reduced to CO2 in a few hours in the
atmosphere. Oxides of nitrogen may be a little more durable but not
much. Cat converters are a cancer on the ass of America and produce
only short term improvements, relevant only in cities like LA and
Denver. Where I live emmissions control does nothing for average air
quality except in a really bad traffic jam.

And I'm not worried about the federales whatsoever. The State guys
could cause trouble but they have to prove I was the one who did it.
Even so all they can do is make me fix it.

 

Nothing like a liberal treehugger to spoil a realistic Technical
Conversation.

 

Of course, you forgot that when hydrocarbons are reduced to CO2 in
the atmosphere, this happens by combination with NoX, which produces
ozone, which is a serious pollutant in the lower atmosphere.

Not true. In fact NoX emissions are the worst of all. At lower levels
they combine with hydrocarbons to produce ozone. In fact, if enough
sunlight is available the chemical reaction continually breaks apart
and puts back together the NoX molecules, this process continues
indefinitely, consuming hydrocarbons and spewing out ozone. As plants
produce a large number of hydrocarbons, introducing NoX into the
mix will create large amounts of ozone.

At higher levels in the atmosphere where there is higher solar energy
available,
and fewer to no hydrocarbons, the reaction is quite different, instead what
is consumed is ozone itself.

NoX is mostly removed from the atmosphere by rain, creating acid
rain.

Not perhaps at ground level, however it does destroy the ozone layer in
the stratosphere. Why do you think incidence of skin cancer is so high
now?

No, what they do is if your a shop and they think your doing this they
run a staged vehicle through your shop, and if it comes out with a punched
cat, then they give you a choice of either paying a fine or fixing it for
all
the customers they think you punched cats on.

If they keep getting reports that your still punching cats then the next
time
they run a staged vehicle through and it comes back punched, then they
don't bother giving you the option to fix the cats anymore, they just
fine you. And what your missing is that the very reason that this is an
administrative violation, is because the state doesen't have to meet the
burden of "beyond a reasonable doubt" if you try fighting it.

This is why speeding tickets aren't misdemeanors, didn't you know that?
The very reason that the states keep them administrative violations,
rather than actual criminal actions, is because as long as the ticket isn't
a crime, the accuser (the state) isn't legally required to prove anything.

You should talk to a few people someday that have been fined for
exceeding their fishing or hunting tags and see just how much the
state had to prove.

Also with the newer vehicles that have post-cat emissions sensors,
your never going to be able to get the check engine light to turn off,
which kind of limits your ability to resell the car.

Ted

 

Yes but I'm not a shop. And on later vehicles I'd get new firmware or
go to an aftermarket programmable ECU... or you build an analog sim to
put the postcat sensor input in acceptable parms. It's a voltage or
resistance, use a pot or build a little adjustable power supply (also,
basically, a pot.) I stay away from electronic vehicles for the most
part.

 

so we should have these removable and only install them in traffic jams??

 

That was a realistic conversation??

 

How so? What do they do/cause/prevent that you object to?

If that's the case, how come they've been adopted as the heart of emission
control systems worldwide?

 

Then your statement that "we punch them" is pretty rediculous, don't you
think? What you mean is "I punch them on my own cars" Why assume
everyone else in your neck of the woods is a trailer trasher?

Spoken like someone who has never actually tried defeating a post cat
sensor.

Hmm - well I suppose that there will be enough old eggbeaters out there that
people want to dump to keep you in cars for the rest of your driving days.

You should be proud of yourself, you are serving a useful function -
relieving
all those people of having to pay to tow off their old heaps. I just hope
you
aren't dumping them in the stream in the back 40 when you can't get them to
run anymore.

Someone has to buy all that duct tape.

Ted

 

It would seem to me, mind you, I don't know my ass from ice cream about
this sort of thing, but it seems to me that all it would do is dilute the
emissions, by making them hotter. Less particles of [whatever it is that
comes out]= lower emission count at the testing station.

I'm probably wrong, though.

 

Um...yeah. You're wrong. *VERY* wrong. That's not how a catalytic
converter works at all.

A catcon has two sections: a reducing section and an oxidizing section.
Reduction and oxidation are two opposite chemical processes. In oxidation,
Oxygen is combined with another element to create a compound called an
"oxide". In reduction, oxygen is removed from an oxide.

The reducing section of the catalytic converter is upstream of the
oxidizing section, and in some systems is housed separately. Its job is to
_reduce_ Nitrogen Oxides ("NOx") into Nitrogen and Oxygen.

The oxidizing section of the catalytic converter then oxidizes Carbon
Monoxide into Carbon Dioxide, and unburned hydrocarbons into Dihydrogen
Monoxide (water) and Carbon Dioxide.

DS

 

Yes, you are. Completely wrong. It doesn't dilute the particles by
making them hotter, it finishes the combustion so the hydrocarbons
aren't particles at all (nor hydrocarbons, for that matter) and the
carbon monoxide is now carbon dioxide. They also break down NOx into
nitrogen and oxygen.

 

Most of them are jerkball yuppies in my "neck of the woods". I
usually have a hard time finding the kind of project cars I
like-between 1965 and 1985.

My current fleet includes a real Meyers Manx with a real Porsche 912
engine (three piece case and all), a couple of diesel Benzes, and a
'79 Chevy pickup. They are all pretty nice looking.

They were all bought not running cheaply and i did fix them up. They
get cruncherized usually not when they "can't be made to run anymore"
but because they have so badly rusted or have been in collisions that
repair is impossible. Of course I pull out all the mechanicals.

My next vehicle will be a Jeep built from a new aftermarket frame and
body. I hope to be able to license it as a 1973...

 

Well, technically not all cats have a reducing section. The early ones
didn't.
Also I don't think the ones they use on wood stoves have the reducing
section
either.


Ted

 

I believe also that there isn't a reducing and oxidizing "section" per
se, as in front half is one and back half is the other, I believe that
this is accomplished with two layers of different catalyst coatings on
top of the washcoat. The layers are fairly porous and thus the exhaust
gas gets to both layers where the magic happens.


Matt

 

Be careful with that Dihydrogen Monoxide - it will kill you if inhaled. 8^)

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

That's nothing compared to the expansive phase change that will occur if
it is not stored and transported below 373.15K at all times...!