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Need to buy a CAT, California legal!

Acura Integra 1999 Auto

Looking to buy a CAT.
California legal requirement reduces supply hence its pricey.
Are there any specialist shops to buy or even a good quality used one?
Ideally I want a direct fit

Looks like the difference between $100 and $500 plus. Rock has an assortment. Cost of living in Cali or check a junkyard.

I don’t think junkyards can legally sell you a used one if they cannot test them before they sell them.

Your state does not allow you any options to buying a new CA certified version.


How would they know? You put on a new cat, it works, all tests pass and no DTCs, how would they know the cat isn’t CARB certified?

The cat is marked and the inspector knows to look for those marks to confirm it is CA certified.

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Do they actually crawl under there to check?

Don’t know firsthand how they check. I’m not in California. I’ve just read that they are very picky about stuff like that. Maybe the CA poster ( @asemaster, I think he’s in CA) can confirm.

Apparently, in California and New York state, the answer is “yes”. Everywhere else, if emissions testing is required, all the inspector cares about is that enough “monitors” are set to ready, no active DTCs are stored, and perhaps an additional tailpipe test shows no excessive pollution. So for those of us who live somewhere else, all that’s needed is a functional cat which will fit.

@db4690 is in CA and does smog testing out there. I think @asemaster is in WA, although I feel like I remember that he grew up in CA.


I assume integra has 1 cat as it’s a 4cyl. I wonder if you could find a new CA cat from anther car that’s cheaper and weld it in?

This is California , just use a certified Muffler shop and have the correct paper work and just move on. Good chance that there might be other exhaust problems also .

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No. In California, you have to use a cat which is C.A.R.B. approved for the specific year, make, and model with the specific engine your car is equipped with. In any other state (except NY) you could have an exhaust shop weld in any cat which can be physically made to fit, and which will reduce pollutant levels sufficiently to keep the CEL off.

I don’t remember exactly anymore but I replaced the cat on my Buick myself with a Rock cat. There was some kind of certificate or form or something that was supposed to be filled out if I remember correctly. Maybe just to have on hand for a shop. No shop though is going to risk their business by messing with fudging it. Like I said, businesses pass costs on to the consumers so they have no incentive to weld in a non-compliant cat.

We all get to the point where for one reason or another question whether a repair is really worth it or not. For a 99 Integra, spending prolly $1000 or more for just the exhaust may be that point where it’s time to say good bye. Mine rusted off the pipe so a straight pipe was not going to allow using the car, and it had already been welded back once. Plus only $100 and a few hours work.

Well I was born in a suburb of Los Angeles and grew up there, then moved to the Seattle area where I lived for the next 25 years. Then 5 years ago I moved to a smallish town in Western Oregon. But enough about my biography…

In CA the tech doing the smog test SHOULD inspect the catalyst to ensure that it is a CA compliant model. If that happens 100% of the time is anyone’s guess. There is a fine and possible suspension of licensing if someone does not properly inspect. But it’s been a long time since I lived in CA. I think @db4690 will be the authority on this one.

I could see where they would check the cat for certification IF the vehicle had failed a smog check and had a citation. They would want to validate the repair. I don’t see where that would be a regular practice for every vehicle that comes through the door. If someone found out they needed a cat and installed it themselves before the required smog check, then why would the inspector check the cat? Would they check every smog device on every vehicle to see if any of them aren’t certified?

Yes. That is part of the state smog inspection. The test facility must verify that all emissions control devices the car left the factory with are in place, operational, and certified for use on that car.

You can put all kinds of performance devices on your car as long as they are CARB compliant.

In Washington state, a car would pass the emissions test as long as the tailpipe readings were below the limits or the OBD testing passed. Way back when I could adjust the carb and timing on a car with no catalyst and get it through emissions. Not so simple in CA.

I can only speak to the smog inspection shop that does my cars. The waiting room has windows to the service bays and I have never seen them look at a cat. On my cars, the cats are tucked tightly between the engine and inner fender below the exhaust manifold and they are not really visible from top or bottom.
Used cats cannot be legally sold in California so if someone wants to sell you one, it is probably stolen. No legit vendor will ship a 49 state cat to California. You would have to drive out of state and give them a fake address to get a 49 state cat. I thought about it.

Are you expecting reasonable, common sense, regulation from the state of California?

Never going to happen.


@Mustangman, you’re right, my bad.


Sadly, it’s not just CA anymore. On the plus side, wider usage might help bring the price down some, but part of the price is the larger amounts of expensive materials.