catalytic converter

You know how sometimes your vehicle just doesn't feel quite right, but you can't really point to anything that's a problem? I've been having that uncomfortable feeling for a while, and I just got to wondering how a person can check the catalytic converter. I had a truck that I bought because it wouldn't run, and a replacement of the catalytic did the trick. Do they slowly become stuffed with garbage and slowly deteriorate the car's performance, or does it just suddenly happen? I have a 1977 350ci. Most everything is new, but I haven't done anything to the exhaust yet.

Reply to
BDragon
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I've never had a "stuffed" catalyc converter..(although I've heard of this being a problem) I can tell you though, that I had a broken baffle in a muffler and after replacing the muffler.. the car ran way WAY better.

-Stan

Reply to
sbright

A '77? I'd say it's a decent chance the converter is plugging.. Back in those days many people would run leaded gas in them and that would melt the honeycomb...

Has the gas filler area been knocked out to fit a leaded nozzle?

BDrag>You know how sometimes your vehicle just doesn't feel quite right, but you

Reply to
RicSeyler

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Reply to
WayneC

Didn't they run the large ones with the pellets in them back then? They were notorious for going bad. Mine did on my 75 Monte Carlo in 1979.

Reply to
JG

Reply to
RicSeyler

No, the filler is for non-leaded only. Since I've had it, it has only run premium unleaded gasoline. The condition of the entire exhaust system makes me think it has probably undergone at least one change. There are no holes, and very few dents.

Reply to
BDragon

Could you be a bit more specific on using the O2 sensor. I don't understand how to do this? Thanks.

I wouldn't mind doing the infrared temp gun check, but I'll have to check on the price of that piece of equipment first. Might be one of those things I would want someone who already has a gun do. Would there be other methods of testing that temperature differential?

Smacking it is something, however, that I can do, for sure. LOL. Thanks.

"BDrag>

Reply to
BDragon

Didn't the ones with the pellets end up smelling like rotten eggs? This one doesn't have the bottom dump in the catalytic, which is another reason I've been thinking it has been changed out somewhere along the way. One time, in its history, the car left the road -- didn't roll -- but I understand it went broadside into a field and caused some damage. Maybe the exhaust was replaced then, which is about twelve years back. I've had the car for about four or five years now, and for three of those, it just sat. So it might have had eight or so years of running on it. It was definitely a daily driver back then.

Reply to
BDragon

Thanks for the links, Wayne. I'm on my way to take a look.

Reply to
BDragon

Wayne, let me thank you again. Those are very informational links that are now on my favorites list.

Reply to
BDragon

Thanks for the info. I'm going to give it a try. I'll let you know if I find anything out.

Reply to
BDragon

Reply to
RicSeyler

I thought about that, but I have an O2 sensor I just took off of a Dodge Dakota. If that fits, or if I can make it fit, I'll try it. Otherwise, as you say, I guess I can always do it the easy way and take the catalytic off. I'm not even sure why I started thinking about the converter, but I guess I'll have to check it just to be sure, now.

Does anyone know if, in California, it is legal to run exhaust straight through to the back and put TWO catalytic converters on the vehicle - one on each side? I started wondering, not that I am going to do that, and didn't know the answer. I know the expense would be prohibitive, but is there a law about this?

Reply to
BDragon

Now I think, but not sure on this.....

1) They will look for anything that is different than stock, excluding parts with CARB Numbers. 2) They will put it on the sniffer to see if it passes...

So as far as I understand (which might be wrong) if they see 2 CATS and the car came with one you would fail, even if the car passes the sniffer.

I'd think the ONLY important thing would be passing the sniffer no matter what parts were on the car. Now-a-days a person could build 500hp and pass any state emission tests. I don't see the harm. But I'm not a politician. hehehehehe

BDragon wrote:

Reply to
RicSeyler

As far as California is concerned, Ric's got it right -- it's bureaucratic and political. The California Bureau of Automotive Repair (BAR) goes by a Bible that for other than mass produced models is error prone. We (me and the BAR) used to play the every-other-year smog game with my gray market 911, bought in Europe. It always passed the sniffer but had a distributor that wasn't on the list of approved items. The car would fail visual inspection at the local smog guy and I'd go the 40 mile drive to the "referee station" (a private contractor that answers to no one). They would issue a notice of failure. I would mail that to Porsche America in Reno. Porsche would return a form letter that my distributor was an "authorized substitute."

Back to the BAR referee station with the Prosche letter. They would pass the car. Two years later it was back through the same process. The prior correspondence didn't count because the manuals hadn't been revised to include my distributor. Etc. Etc. Etc.

Finally, I got smart and took the critter to a Prosche dealer for smog. California law let the dealer sign off on the distributor, OK the car and pass it. $ 105 bucks for a smog inspection at the dealer was cheaper than $ 45 at the corner smog guy...figure.

These people look at the VUN. For a given VIN there's a configuration list of things they look for. If I had taken my European 911 and upgraded it with all California approved components it would have failed.

I have seen inspection options on the smog testing machines that provide for two CATs but don't know what that might mean. I fear that getting the two banks into the ball park might be tougher than the average of the two -- maybe an ECM averaging two O2 sensors??? Next time someone goes for smog it might be a good deal to ask and post the answer here.

PJ

Reply to
PJ

Reply to
BDragon

Snip

Actually it's getting more complex than that. My 04 had 2 pre-cats and 2 cats with a pre burn and an after burn o2 sensor for each side. The computer is reading the exhaust input and then its output to make fuel trim settings.

What one state says will mean nothing to another states set of laws, most of all Kalifornicate. The federal laws state that it must be as it came from the factory, any modification to the exhaust configuration is a no no. Even the add on split after the muffler is not legal but not enforced by states that don't have mandatory exhaust compliance testing.

The only out I've seen is the age of an old car making it exempt and that is getting scarce.

Reply to
Dad

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