80 Series Exhaust Noise / Cats?

1973Guppie

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Hi All,

For the past several months I have been getting a metallic rattling noise upon acceleration in my 96 80 series. I went under there today and am fairly sure it is the cats that are making the noise. I recenlty had the vehicle smogged and it passed just fine but the noise is driving me crazy. I recently had the muffler replaced as the baffles came apart inside and were blocking and causing major noise. The muffler I have is a POS and I want to replace it. Won't ever go to MIDAS again. The cats are fairly rusted, and they are flaking off quite a bit. I went under there with a rubber mallet and when I hit the cats I get a loose rattling noise for sure that sounds similar to what I hear upon acceleration. The good news is that the pipe from the engine seems in good shape. I am thinking I am going to have to replace the cats.

Question: what are the telltale signs of a cat going out? have others had rattling issues when their cats go bad? I am thinking it is rusting inside that is basically coming apart and rattling. This happened with my muffler as well.

Question: what are the options out there for high flows cats? I know there are vendors on this site but unfortunately I live in CA and it has to be CARB approved for CA for me to buy it. (nazi's here). Does anyone make a high flow performance cat for the 80 series? I know I can get OEM but really don't want to spend that much.

thanks!

Noah
 
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noah, the heat shields on my cats rattle occasionally at startup. that could be your problem. nothing wrong just a little loose.

not really anything but an annoyance. i could tack the two shield pieces together if it really bothered me.
 

1973Guppie

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I pulled those side heat shields awhile ago, it is definetly coming from inside the cats, anyone know of a CA smog legal replacement cat? I have found several but they are all 49 state, godamn CA.
 
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What did you end up doing for this guppie? I'm having a similar noise under cold acceleration, and I also have a P0420 check engine light on (most likely 02 sensors or cat). Coincidence?? Did you fix yours with new cats?
 

1973Guppie

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the noise actually ended up being that weight "thingy" that hangs down from the transmission, took it off and no more noise, it was rubbing against my ipor skidplate and made a racket upon acceleration.

Since then, I have had my exhaust redone by a local shop, they pushed up the cats and did a nice job. I posted it up here somewhere along with some pics.

Noah
 

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