I was looking at my old Catalytic yesterday, and i noticed that the bung for the 02 sensor seems to be before the cat does anything to the exhaust gases. If you look through the cat-side where the exhaust would flow into, you can clearly see the 02 just stuck in there before any screens or anything. How does the sensor measure if the cat is doing its job? Does it measure temperature; and a clog, or anything under optimum flow would cause raise in temp?

 

There are two O2 sensors... The front (before the cat) measures the oxygen in the exhaust and sends the information to the ECU (along with many other inputs) to determine fuel trim. The ECU compares the front and rear O2 sensors (after the cat) to determine the catalytic converter's performance. If they are too similar, the cat is not doing it's job.

 

Are you asking why the sensor is part way into the cat rather than after it?

Read this post
https://www.rx8club.com/showpost.php...7&postcount=10

 

is the sensor that is part way into the cat the rear one? I'm asking this because if there is supposed to be 2 "filters" in the cat ( the sensor sitting between them) then mine appears to be missing the front one... i can see the sensor while looking into the cat...

 

The front O2 sensor is in the manifold.

The rear O2 sensor is in the middle of the cat between the 2 cat elements.

If you can look in the front of your cat and see the sensor tip, then you are missing your front cat element.

 

alright, and i bought it like that from the dealer.... are they entitled to replace it.. they sold me a car that should not have passed inspection. It was a mazda dealership btw, the same dealership that replaced the engine. They should have noticed.

 

So do you see any elements at all or is it a gutted cat?

What area do you live in?

 

Depends on the liability / warranty that the car was purchased under, and state law. If they didn't actually put anything in writing and the state doesn't have any laws to protect you in that regard then you are out of luck. If the state has laws to protect you or there was some level of warranty, then yes, you have some recourse.

Depending on the mileage and year, there is also a mandatory federal law (US) covering the cat (among some other emissions stuff) for 8yrs 80,000 miles.

 

i have 82xxx miles. Its not a problem if i can't get a new cat i was just looking to make a few hundred dollars. I already have a midpipe i'm satisfied wit, i would most likley end up selling the new cat or keeping it around for inspection. I just think it kind of sucks. The fact that a mazda dealership would sell a customer a car that would inevidably end up costing over a thousand dollars. Also the fact that the car should have never left the lot because it should not have passed inspection.

 

Oh and i live in mass

 

If the car wasn't so e'ffin fun to drive i would have done away with it already. Within 2 months, its needed a new cat, new front breaks and rotors, new tires, and over 60" of oil lines.

 

Take a peek at this then. http://www.mass.gov/ocabr/consumer/a...ranty-law.html

Should have a 30-day warranty by law, and at 2 months you are past that. But some other items might be reimbursable.

And if you didn't get an actual wearranty document from the dealer, then note this section:

 

Well, to be fair... All that didn't fail due to 2 months of use. You bought a six year old car with 82k on it. Brakes/rotors, tires, and a cat are not unusual for any car of that age/miles.

I presume you did a full inspection of the car and knew what you were in for before buying it?

 

Agreed, he needed to research and inspect better. But he still has legal rights in his state that cover him against those same items. Though may be out of luck for not researching his legal rights either.

 

I am fully aware of the 30 day state protection, I was fully aware that this (or any car) is NOT cheap to maintain, I am fully aware that s*&t happens, I did hours of lurking (on this site), I researched my options, and i fell in love with the car. I am capable of maintenance as well as diagnosing and fixing problems (to an extent). However... I am PISSED that the front element of my catalytic converter is missing... for reasons unknown. I bought specifically from a dealer so maybe i would be able to avoid nonsense such as this. The "to be fair" bs is just that... Buying directly from mazda i did not expect to have such problems as half of my cat being missing in action, or oil lines that were so rusted out that they have become porouse like a sponge... and leaked all over my new driveway. I will not be "fair" to a dealership that sold the car in the condition that it was in. The same dealership that wanted 750 dollars to fix oil lines 2 weeks after my "30 day" state protection has expired. I do not appreciate the condescending manner in which you replied about me. You made assumptions that i did not do my "research" and that i am just another sorry member using the forum as some sort of complaint office.

 

In general, yes, we did. Reading over your posts there is nothing there to contradict that perception.

Sounds like you have it in hand though.

 

Posts Have Been Removed: Argumentative and Silly Name Calling.

 

I lost a post from mobile before, but blackAT, we aren't flaming you for getting angry, or even getting screwed. We are simply acknowledging that you could have detected most of the issues (everything but the cat) prior to purchase, but didn't, and the only issue that you couldn't have been reasonably expected to find, you previously said that it didn't matter because you were ditching the cat anyway. Since you could have detected these issues (and didn't investigate thoroughly), and didn't exercise your legal rights within the legal time-span, we aren't really feeling sympathy toward you.

Doesn't mean that we agree with or feel friendly toward the dealer either, since they clearly screwed you. Mostly just a shrug and hope that you learned something from this.

 

I wasn't being condescending in the least. I wasn't defending the dealership, nor was I accusing you of anything. (Unless in fact, you did buy a car with worn out brakes and tires, and didn't do your due diligence to make yourself aware of such things before purchase. And if that's the case, it's less of an accusation and more of a hope that it's a learning experience for you and anyone else reading this thread.)

I simply pointed out, that the issues I listed (brakes, tires, and cat) are typical for ANY car of that age and use. With your comment that I quoted above, you seemed to be blaming the car for having worn brakes and tires.

As for the cat, I will defend the dealership on this. As an auto mechanic of 10+ years, I can say with all assurance, that no shop or seller would know that the cat was bad, if it didn't have any signs short of disassembling it.

 

I wish you had have posted earlier

 

You missed my awesome defence of your character