steveP911

I have been having some CEL issues that I believe may be related to the "aging" of my 200 cell AWE cats. I cannot be sure of their age, because the PO did not have them installed, but I think they are likely around 10 years old. I get the image below on my OBD2 reader.

I have had to reset it three times now in the last few months. It generally happens if I get stuck in traffic and have to idle after the engine is hot. I checked with AWE and the new cats are $1800. I cannot use an alternative because the entire exhaust system is AWE so I have to maintain the interface.

Have others seen this issue with their older lower cell aftermarket cats, and what did you end up doing? Am I going to have to eat the cost of new cats? Thanks for any advice you may have.

EMC2

If it's only happening on one bank I would start with the O2 sensors. It may be possible to swap the sensors from one bank to the other, to see if the problem follows the sensor (if the sensors have same length cable etc).
Even if not, it's a cheap and easy replacement.
Mine is a 997.2 so not sure how much different the DIY would be but perhaps the link below could help:
https://rennlist.com/forums/997-foru...placement.html

OKB

I would try that first. But if its a aftermkt cat, it could be bad. But it seems like it would have a warrantee. all factory cats have long, like 10 yr warrantee. id look at awe web site and call them.

Wolfk

If none of the above work for you, you can install rear O2 spacers. This will defeat the efficiency code and usually is a must when installing high flow cats on other brands.

Petza914

200 cell cats don't require an O2 spacer, but 100 cell or cat bypass pipes do. My 200 cell Fabspeed X-pipe has HJS cats and the OEM O2 sensors and doesn't throw any codes. My car is a 2095 997.1 C2S though.

Wolfk

^ Agree, if the cats are in top condition, however, for aged cats, spacers are an easy option.

steveP911

Thanks for the feedback, guys.

It's always Bank 2 - is it safe to assume it's the O2 sensor after that cat? Maybe that's a dumb question but I gotta ask.

I have contacted AWE. The warranty was two years - long gone.

I'm not familiar with the spacers you are referring to, Wolfk. Do they simply position the sensor a bit farther out of the cat? Can you elaborate on where I could get those? They sound economical and easy to install.

Replacement cats are $1950 from AWE. Plus install, which I'm afraid I can't do.

Thanks again.

lowbee

Why not go to a muffler shop to have the bad CAT cut out and replace it with either a Vibrant or Magnaflow high flow CAT for less than $200 each

Something like this https://www.summitracing.com/parts/m...FUlNfgodx3EAmA

Your custom muffler shop will know which one fits

The expensive HJS cat are great and you pay for the erotic material used to make their CAT very efficient and great at reducing CO2 and other undesirable gases but if you can live with a less efficient CAT then Vibrant or Magnaflow would not be too bad

OKB

have you tried carnwell otherwise, I would look for some other 200 cell cat and weld them in, any of the exhaust like agency power or maxspeed should have same sizes

Wolfk

Yes, cat efficiency codes are triggered by the O2 sensor after the cat. In fact that is the only function that the rear O2 sensors provide.
Yes, O2 spacer pulls the sensor further away from the cat, google O2 spacer and you will be able to view a wide variety. I am not sure of the O2 arrangement on a 997.1, but my 997.2 required spacers that were angled at 45 deg. due to space restriction.

It is also possible that your cat is completely or partially blown out, it is up to you if you want to repair properly.

mcfisticuffs

You can also try O2 spacers with mini-cats. I had a set on my catless X-Pipe and I received no CEL. There are several manufacturers, I had the SpeedTech's on my 996, and have a set of the Maxspeed on order (Fabspeed's were more expensive, and they couldn't honour their shipping price):

http://www.speedtechexhausts.com/ast1_032.htm
http://www.fabspeed.com/universal-o2...ic-converters/
http://www.maxspeed-motorsports.com/...t_Fix%22_.html

Macster

Haven't seen this with aftermarket converters but I saw this -- lived with it for a few years -- with the factory exhaust of my 2002 Boxster.

The factory repair guidelines say to if the P0430/P0420 error code is accompanied by any aging O2 sensor codes to replace the indicated sensors and clear the codes and road test the car. If the P0430/P0420 error comes back replace the indicated converter.

In the case of my Boxster the error was due to a loose converter brick that only once in a while -- sometimes not for months -- would get out of position and operate at below a suitable level of efficiency. I managed to get the car through several smog checks/tests with no problems.

Primarily it was the noise -- a dull deep knocking when cold and a buzzing -- like a loose piece of metal shielding -- when hot -- that finally had me replace the original exhaust manifold with one sourced from a salvage yard.

If the converter was working fine before I fail to see how fitting O2 sensor standoffs will help. The problem is the converter is not able to retain oxygen which it needs to retain during those times there is an excess of oxygen in the exhaust gases for use to convert other exhaust gases.

The #2 O2 sensor voltage readings (monitored by the DME) clearly shows the oxygen level is elevated when it should not be.

If the converter brick is secure and there are no exhaust system leaks what has probably happened is the converter has shed some -- too much -- of the very thin layer of catalytic metals that are on the surfaces of the converter. This assumes you have not been using an oil with excessive level of ZDDP. (In the high temperature environment of the converter (approx. 600C or 1000F) ZDDP can form a glass like coating on the working surfaces of the converter which lower its efficiency.)

In either case: catalytic metal has been lost of the converter's working surfaces contaminated by some oil additive; replacement of the no longer working at a suitable level of efficiency is required.

'course, you can try the O2 extenders. While I'm having a hard time coming up with a plausible theory as to how these can help in this situation the extenders are I dare say a heck of a lot less money than at least one new converter (and the other side could be near failling too).

Ahsai

These? http://www.awe-tuning.com/awe-997sexhaust

A good muffler shop should be able to cut the cat open and replace the insert inside to retain the same look. You can check HJS inserts to see if they have the right size. Most likely they do.

Carnewal offers such operation but on stock cats. Maybe you can check with them if they can do the same on the AWE cats.

Ahsai

Like these

http://www.fabspeed.com/hjs-catalytic-converters/

Carnewal charge about $1k to do both cats.

John@Fabspeed

Steve, have either yourself or a shop pull take out the O2 sensors and stick a scope/camera down and take a look at both side of the cats. If there is no physical deterioration of the cats then they are just not scrubbing the exhaust within factory specification. In that case you do not have to replace the cats themselves and have two options.

1. Purchase a set of our O2 spacers ($150 for a set) and space out the rear O2 sensors from the exhaust stream. This will simulate a stronger cat reading and likely put them back within specification for you.
2. Purchase an ECU tune ($995), as our tuner can not only shut off the CEL but can squeeze a nice bit of reliable HP/TQ out of the car as well.

If the cat cores are physically deteriorating, give me a call and i'll take care of you as best I can on a new set of our Sport Cats