guster900

Hi, first post here, and am very glad to find these forums. I have been working on fixing up my old tiburon for my younger brother, and am currently replacing the header/cat & O2 sensors. I have a 2000 Tiburon, and have read about front & rear cats for this year. I can not find a definitive answer on if my year has one or two catalytic converters. I have looked the exhaust over and can't see a second one... but thought it might be smaller or under a sheild or idk... if anyone can shed some light on it for me I would really appreciate it because I can buy them online, or ones listed as "rear", but I dont see a rear one.

Also, I am replacing it because there is a CEL and was told it was the cat when the code was pulled. There is a severe lack of power/acceleration when starting out. Could this be from bad O2 sensor(s) & bad cat/headers?
Thanks!

likeyoumeanit

well, the second O2 sensor only monitors the cat's effectiveness for emissions and has nothing to do with the tune, the first O2 sensor monitors if the engine is running rich or lean. The code should tell you which sensor is having an issue. As for the lack of power it could also be a clogged cat. If you're not in California you can probably get away with not having the second cat even if you originally had one.

guster900

<div class='quotetop'>QUOTE (likeyoumeanit @ Jul 26 2009, 12:23 AM) <{POST_SNAPBACK}></div><div class='quotemain'>well, the second O2 sensor only monitors the cat's effectiveness for emissions and has nothing to do with the tune, the first O2 sensor monitors if the engine is running rich or lean. The code should tell you which sensor is having an issue. As for the lack of power it could also be a clogged cat. If you're not in California you can probably get away with not having the second cat even if you originally had one.</div>

Is there a way of knowing which cat is bad, front or rear? But my main question...... how do I KNOW if I have a rear cat? I pulled the front one today along with the headers, the full unit. But I looked and couldn't see anything I thought was a second, rear cat. Where is it located at, whats it look like? I know what a normal cat looks like and didnt see anything. Is there an easy way to know if it had a second rear cat based on make/model/year? Or is it jsut based on California emissions? Which in that case, i wouldn't think I should have a second cat, since I'm in Ohio, and the car was purchased here.

frozen

There are a few threads from a while back discussing this. Some have 2, some don't. If you looked at the exhaust from underneath the car and didn't see anything besides a muffler, then you don't have one. It's not disguised or anything.

Typically if a cat is going to clog, it's the first one, that is where the exhaust gas is hottest and does the most damage to the cat. If your 2nd cat clogs it's probably clogged with peices of the first cat.

i8acobra

The first cat sits vertically in front of the engine. It's part of the manifold. The second cat is under the car, right after the oil pan.

guster900

I just took out the second O2 sensor, and looked at the exhaust again. I will be replacing all of it in 6 months or so, it's rusty, but all still solid. So I have been looking online at the 'rear' catalytic converters, and don't see the same thing as what is being sold. They are all bolt on OE types, or universal weld on ones.

After the 2nd O2 seonsor, there is one pipe that bolts on and goes all the way to the muffler. In the middle of this pipe, there is a one or two foot section where the pipe doubles in diameter and it looks like that peice has been welded in, but it still doesn't look like a catalytic converter to me. The front catalytic converter that I pulled, looks like what I think of as a cat, but not this part. So I have posted a few pics, one before, mid and after this section of pipe. Maybe one of you can tell me if it is indeed a lower cat, or if not, what is it?
Thanks (sorry for being a bit stupid with all this)

radu_rd2

Not sure, but that might be just a resonator, doesn't really look like a cat to me. Second cat is usually close to the flange you have in the first picture, to the left
So you probably have just one cat. I think there is some emissions info on a sticker inside engine bay, should say whether it's california compliant (2 cats) or no

frozen

As radu said that is a resonator not a cat.

guster900

<div class='quotetop'>QUOTE (Frozen @ Jul 26 2009, 01:23 PM) <{POST_SNAPBACK}></div><div class='quotemain'>As radu said that is a resonator not a cat.</div>

That's great to hear! I certainly didn't want to buy a second cat. Resonator was the only thing I thought it might be, but had to ask since I am no expert on exhaust. Thanks!

i8acobra

They have bullet-style cats, so it's possible that is one. Whatever it is, it's aftermarket.