Pinto Car Club of America

What are the signs of a plugged or bad CAT?  I had new exhaust put on my 79 wagon today.  The guy said my cat is bad and I should replace it yet my car passes smog?  The exhaust pops at times and he said that was due to the CAT being bad.  Not sure what to believe.  I don't really want to spend any more money at this time but again I don't want to mess up what I just had done.  Any info would be appreciated.

 

Are you losing power or using an unusual amount of gas?  Have someone follow you up a long steep grade, and see if they smell rotten egg smell.

I had a cat get plugged up once.  The exhaust from the manifold to the cat. would get red hot.  I cut off the cat. and with a stick hollowed it out and put it back on.   That way I was still within the smog laws.  It worked fine after that.

Were you told WHY it was bad? If not, go and ask.

Smell is not the best way to test them, nor is hollowing one out "legal"(depending on the state, my state does not seem to care about cars 25 years old or more. no look, no sniff).

If you lightly bang on it with a rubber hammer, do you hear a rattle? They tend to come apart inside, that is one way they go bad and still pass a sniff test. Sometimes they do clog, most of the time from running too rich. Poor performance (how to tell what that is, in a stock pinto) is a good sign that is cloged (if all else is ok). That popping might be that you are running rich, and/or there is a hole in the pipe/cat.

Bill

If your car passed emissions test and it runs OK with normal power, then you will not hurt any of the new exhaust