I have a question and it might be nothing , but I just needed some advice . How do you know when your catalytic converters are going bad? When I'm on the road and going the speed limit then decide to get on the car a little , I get the smell of sulfur ( just on first hard acceleration). Car drives great with no hesitation and I just passed a state inspection . I just wanted to know if this smell was normal or if I should have something checked .

 

If the cats toast you would have failed inspection and you prob get a check engine light or even hear rattleing. The smell is IMO the film thats on the exhaust.

 

Sulfur from gas and occurs under heavy acceleration (rich mixture). As stated above, you would have failed smog if your cats are gone. The o2 sensor will also send signal to your computer.

Just watch it for now.

How many miles on the car?

 

Wait'll you get a check engine light to replace your cats.
The sulfur could be brakes or clutch, but noting a bit of a scent isn't unusual and doesn't mean there's an issue with either.

Regardless, when it's time to replace your cats, without a doubt get a set of AWE's. Ask for Michael Romano and tell him I sent you
CATTMAN

 

love my AWE cats

 

You can determine if your cats are weakening and near tripping the CEL. Unfortunatly, I don't remember the exact perameter to check, but my mechanic hooked up the Porsche computer to my car while it was running and showed me live values of what I think was the 02 sensors after the cats. (Maybe it wasn't as I think about it but I just don't remember what parameter it was). He said that the graph line created by the computer should be relatively flat and mine was like a sine wave as the computer was trying to compensate for something. He said something like "your cats are near end of life".

As I understand it, any mechanic with the proper tools, Porsche computer or Durametric showing live values, can determine this.... if you really want to know.

Peace
Bruce in Philly

 

Try a can of seafoam first. For some reason that crap fixes just about everything.

 

Thanks for all the input . If anything I'll just go with the aftermarket... Thanks again ..playing it by ear ....

 

On my 996 they actually started rattling at or around idle. Couldn't tell a difference performance or smell-wise. It was covered under warranty by Porsche, I think it was like a 7yr/80k warranty on emission stuff?

 

Cats are mechanical. Inside is a screen with a ceramic like coating in a somewhat honeycomb finish where the exhaust passes thru. Two failures that I know of:

1. They clogged up or
2. The ceramic material disintegrate resulting to rattles.

In my younger days, i actually used a broom to gut out the cat (cheap way to have a bypass).

I believe that emission stuff have the longest warranty regardless of car make -- the long warranty might be mandated by law.