Ok, I went to the estation today. I'm do in May so I figured why not go today. Well, I failed it miserably on the hydrocarbons. My Carbon Monoxide is fine and they didn't test CO2.

HydroCarbons - State allows .80, I put out 2.67
CarbonMonoxide - State allows 15.0, I put out 11.2

They didn't test the CO2, but they put the results down? Wierd, anyways thats 472.5, don't know what the state allows for since it doesn't say.

Before you say change your plugs, I'll have to tell you this. My engine is BRAND NEW, its a reman and it seems to run great. My cat is original, probably vintate 1989, and the exhaust is a 3" cat back.

Can anyone give me some tips to look for? Mechanically it can't be anything in the engine itself because thats all brand new. The heads, block, seals, everying internal is new.

However, anything that was bolt on is pretty much original, with the exception of just about every major sensor in the bay.

 

I believe there's a clue in there somewhere.

 

My guess is that it might be running a little rich at the higher speeds, the cat is used mainly to control CO from what I recall learning in school.

 

Can you say "time for a new cat"?

 

Its one of my fears that the previous owners gutted the cat. I found several interesting things with the car and thats probably one of them.

How can you tell if a cat is bad, is there a way to check it without removing it and replacing it?

 

Sounds like you need to take it off and check it out. I ALMOST passed emissions when I got to California and put the emissions stuff back on my TA. I pulled the cat and found it to be hollow! When I ut on a new one (only $65 later) I had almost 0 emissions!

 

Yeah, but I'm WAY over the limit for hydrocarbons. Standard is .8 and i"m at 2.67!!! Thats over 3 times as much emissions as I'm supposed to have on average. Thats terrible..

 

I alwasy thought Hydro's were associated with ign timing? May want to check that.

 

Hmm...would less timing create more HC's because of an incomplete combustion process? Guess its time to check the timing.

I still think my cat is shot though. Its also a good reason to get a performance cat, any recomendations?

 

i just bought a universal higher flowing than stock cat and i think it works fine, and i only paid 50 bucks for it brand new....

otherwise, a cheapy performance cat would be the usual flowmaster/dynomax ones and they run more like 175 bucks.

 

I was actually looking for some hard data such as flow, and how well the cat actually works. Its funny, but I don't think there are any articles that really compare different cats.

 

I wouldn't get a catco, one user couldn't pass with it while passed fine with a better one and I couldn't pass with it alone, I needed to invoke a lean condition in the prom. Neither of us, however, had stock cams. By the looks of the peaky CO graph, a new cat is definately needed.

 

What I'm looking for is an article that flow tests them. One that may also provide a test that benches their ability to reduce emissions so i can pass the test better.

I'm also posting because I would like help in reading the graphs to look for possible solutions. I've never had a car fail before and therefore don't really know much about what these graphs mean, along with the numbers. My CO is good, its 11.2 out of 15.0, but the HC is way off the charts I think. What is this usually indicitive of?

An article very similar to this would be helpful. http://www.installuniversity.com/ins...n11.122001.htm

 

Your CO may be passing, but it is very high for a good running car. Actually, all of your tests are peaky, from my experience with emission testing indicates a poor performing cat. That will prob pass you no problem. Check out my graph, notice its perfectly flat except for idle, and decel.(DFCO) CO is nearly non exsistant under cruise and accel. This was running a hotcam with an ARAP prom, no emissions devices except for the cat.

 

That sounds about right then. It can't be the engine because the engine is brand new from the heads to the bottom end. So whatever problems I have have to be either faulty sensors, or something else.

Guess its time for a cat then. Though they usual indicators aren't there. My car still revs like crazy at WOT, and still pulls decently at highway speeds. It doesn't show any of the normal won't rev symptoms for clogged cats.

Originally when I bought my car it had a cracked block and coolant was pouring out into two of the cylinders. Could the coolant that was passed through the exhaust have destroyed the cat?

Now we are getting onto what cats are shown to be the best. Should I just got with a stock replacement? Or can anyone provide solid evidence that a high-flo cat actually works well, and provides less restriction?