tkerrmd

Can anyone shed some light on this subject. Lots posted on modds and esp exhaust changes. I guess that is ok if you just want a "sound" change.

But, what if you what a hp change? And would like to go to 100 cell cats or cat bypass? What is the current plan on the oxygen sensor and the CEL warnings.

Can this be "programed" out and if so safely?? Or does one need one of those "fake" sender units to "trick" the computer and is that safe??

Also have had friends put 100 cell cats on and still get the CEL and they still drive the car and ignore it!! Then you never know whats going on...

I know alot has been said about this topic and I apologize, but bottom line, if the cats are replaced with a "bypass" what needs to be done to keep everything else ok with the engine and oxygen sensor.

sorry for all the dumb repetitive questions, just want to learn from others experiences so I dont have to do the trial and error thing!!!!

thanks in advance!!

tom

Dock

My Europipe 2 has 100 cell cats and I've never had a CEL.

Oak

my ruf has 100 cell cats and doesn't trigger CEL. if programmed correctly should not trigger CEL's.

tkerrmd

thanks guys, but what is the CEL light comes on with "100 cell" cats, can something be done about that?
have a cargraphic exhaust and CEL on? I will call them but just curious, since you guys have so much experience, I appreciate the responses.

Just as an aside, what about going to cat bypass. Problems then???

thanks again

tom

Oak

tom, I had a Cargrphics Export version in the past and had no CEL triggered by the cats. Are you sure the Cats are causing the CEL's? The Cargraphics Export I had installed had 200 cell cats. Do you have the CEL codes? It's most likely a air leak in bank 1 or bank 2 causing the lights to appear.

Zippy

I ran an Europipe Stage 2 Loud with stock everything else for a few months and had no CELs.

Mike

wross996tt

Get the code (get a scanner). It could be the O2 heaters (actually use a heater to egt them to temp faster). If so the units must be replaced.

NC Bob

I"ve had the B&B LeMans system with 100 cell cats on for 20,000 miles. No CEL issues ever.

Woodster

I have PSI "loud" exhaust and it triggers no CEL's. Currently stock programming.
MK

tkerrmd

thanks for the infor and suggestions, I'll get on this. would like to go not cats and ? do I need a muffler??? Car only driven to track and occasionally to impress neighborhood kids!!

forum is great source of info couldnt get locally, thanks again

tom

BigCarrot

I'll bite. I put the Fabspeed quiet on mine, and I get CEL's. I'm wondering what I should do about it. I'm thinking I'll just buy one of those cheap code readers from Autozone, and erase them when they do pop up.

DT04R

Howdy!

Have any of you tried running 02 sims? I'm assuming that the CEL is triggered by the 02's downstream from the cats? People who run headers on Vette's and don't have or want to do alter the ECU just plug these in and they simulate the proper signal regardless of airflow/temp/etc.

Otherwise the 2nd pair (the first pair on a LSx car is before the cats and used by the ECU to tweak the AFR tables) on my car for instance triggers a ODB 0803 (low operating temp) because the exhaust flows quicker and cooler and they sometimes don't get up to temp quickly. Actually I used HPTuners and just removed the 2nd cats as an error source

This is a great topic, since I won't be leaving the TT stock when I get it

tkerrmd

thanks BigCarrot, seem to have same problem!!! Good thread, I'm not sure what to do, dont want to drive with CEL on cause I'm at the track alot. I'm going to follow some of the above suggestions and I and hopefully others will post some answers to this and for me what to do if use cat bypass.

thanks

1999Porsche911

Spend a few bucks and get a good scanner. Then come back and tell us what the codes are and what the engine was doing when it was set.

GreggT

Correct........get the codes......be able to easily reset........subscribe to RennTech and get Porsche ODB code explanations.
Least expensive glove-box reader that's any good at all (IMHO) is the PocketScan from toolsource.com.......you can spend more, you can go PC or Palm based.

But, at least then you've taken it from an 'idiot light' that can be telling you a couple hundred dif things.........down to the actual symptom (or symptoms). Till you know that, you have nothing to work on.
Just my opin but for most any signif change under the hood, you have to have the OBD II codes in mind. If you work with a tuner, they do (or should).