Alright I'm pretty convinced that my cat is clogged.

Here's the story:
Every time I floor the pedal, the exhaust stinks. I've stuck with name brand gas (exxon, amoco, chevron) etc. for the past 5000 miles and I'm still getting the stink (tho i think it has improved, never the less STILL THERE). I can only duplicate this stench when it's in gear and above 3k RPM. I still have a basic warranty until December if this year, so I want to prove it to infinti so they can replace the cat. Now the question for you folks: How do I go about doing this? Any relevant ideas welcome.

Thanks all,
John

 

Clogged cat = horrible gas mileage, a super quiet exhaust, and a noticeable drop in performance. Not slight, noticeable.


Dave

 

some places can perform tests on the air flow of your exhaust...can tell you have a fuxxed flex section in your y, clogged cat, etc.

 

I remember it being said to get under your car and bang on your catalytic conv. with your fist and see if it sounds like there is bunch of stuff rumbling around in it....
bt i'm not sure if it means it's clogged or blown... if there is even a difference ...

 

I have heard before that to test and see if you cat is clogged put your hand at the muffler and feel the air coming out. It should be puff puff puff puff instead of a constant flow. I did mine and it went puff puff. Someone please correct me if I am wrong but its worth a try.

 

Your right. Thats a very good test. You should hear and feel your cars exhaust system at the tail pipe. If your tail pipe just sounds like a hush with no pulsations at idle then your cat is clogged.

 

Isnt there also a way to tell by the tempature? Like before and after the cat? I read it somewhere before but forget the actual way of doing it.

SuDZ

 

ok, i'd like to add a question...I bought a used high flow cat (random technology)and it looks like it might be a little clogged. I'm not sure if it is or not, but if it was, is there any way to "unclogg" it or flush it out? I got it for free and i don't want to spend $185 on a new one...Thanks.

 

Nope.... no way to clean it. Not for less than the cost of a new one anyway...

-RMB

 

Here is the tool you'll need to test the back pressure.
Exhaust Back Pressure Tester Tool

 

rmb, thanks for the help, i guess that mod will wait...

 

Will checked the exhaust tonight when the engine was warm.. It's puttering away. *sigh* well so much for that proving anything. Anyhow I floored it again, or rather I did some spirited driving with my friend and when we stopped..the stench was back.. FOCKER!
Oh well, i'll see what happens after I installl the y-pipe....

BTW it seems like it's running rich maybe? I know if it's running rich it will produce the rotten egg smell..
ANyhow thought i'd post an update

EDIT: it's real quiet..but I think that's normal right?

 

Here's what you do - Remove your cat from the car when you install your y pipe and look through it for clogged passageways, or melting. you can see the melting immediatly, the clogged passageways: hold it up to a light and look through it.

Federal law requires manufactures to warrant their cats for 10 years or 80000 miles, so don't sweat it. However I have seen auto dealers deny a claim with some sort of exhaust mod, so figure it out before installing your y pipe, and make sure your ypipe is not installed when you take it to the dealer if you have to.

 

My Max had the smell you described, It turned out the oxygen sensor was going bad and I was running a bit rich. Once I changed the sensor the smell went away. Could just be coincidence, but I believe they were related. Also if you are indeed running rich this can cause the catalytic converter to prematurely fail. Don't know if that means clog or what all I know is "fail" Also if there is excessive black carbon build up around your tailpipe that can also be a sign of running rich. It will also adversely effect performance and cause bad gas mileage. Just something to keep an eye on. They can check the fuel ratio and sensors with an oscilloscope at the dealer quite easily, I might suggest that if it's under warranty.