Hey guys,

I have a reflashed (Gemballa...older tune) 2001 Turbo and also a Durametric. I recently installed a cat-less rear exhaust and O2 sensor extenders. Despite having the extenders in place, the car is throwing the CEL for catalytic converter efficiency for the post-cat set of O2 sensors. Although this was to be expected, I was hoping the extenders would alleviate the issue...this was not the case.

Anyway, what are my options for having the rear sensors turned off? I'm aware of getting a tune that can do this of course, but I am already reflashed and my tune has been deemed 'safe' even on the cat-less exhaust. Is there any reasonable/affordable way to turn off these rear sensors without getting a full re-tune?

Thanks for your help!

 

Steve, do your extenders have a reduced opening at the bottom? it will work if you go down to about 5mm. I have found that is what does the trick not just the length...

 

Yes, I have the FVD version (I bought cheapie aluminum fleaBay ones originally...they weren't worth a darn and didn't even allow me to install them, thread-wise) that do bottleneck down to a very small hole at the bottom. These are the 'short' FVD extenders, but are rather long already.

I believe FVD does sell a longer version of them as well, but since this is the only thing I'm looking to change I figured I'd throw the question out there.

*EDIT* I included a picture of the model I have from them.

 

I successfully used these longer version units. Worked very well. I dont know what brand they are. I got them from blockhed

 

Thanks TurboTodd. Those are clearly longer than the standard FVD ones I have. I suspect that in order to avoid a re-tune I will have to pony up and get a longer set like that, as those appear to be as long as the other FVD model as well.

*EDIT* Have you ever thrown any CELs for catalytic converter efficiency on your car since you installed those? Or, do you still get them occasionally?

 

Those from Blockhead are the ones that work for me. Good luck!
Or Blox brand (haha just a coincidence)

 

not one CEL when I was using them. I was really surprised they worked so well.

Now I have the Markski magic custom tune and have the 2nd O2 pluged.

 

Stupid question but regardless of your tune....If you go straight pipes and get a CEL can you not just have local Porsche garage shut off CEL permanently vis diagnostic or something like this?

 

Kerrage,

I don't find it a stupid question at all since that is essentially what I'm asking myself. Meaning, if I didn't want to deal with the O2 sensor extension thing and just wanted the rear sensors turned off, I'm curious about the other ways to go about that (assuming no full re-tune). Thanks for helping to clarify.

 

Some tuners will do it for you but along with their tune and it could be for "off road only" use. Can't re-write another tuner's program though. It is not legal for a "on road" vehicle or tuner to turn off emission related systems. So the dealer can't/won't do it either. No such thing as a stupid question remember!

 

shiza I have RUF tune and would like catless>>right now i think I have 100 cell in my ruf exhaust...no idea if ruf would shut off rear o2...So I am in same boat..wish you could just go in and shut off....or modify tune easily without a chance of messing up my expensive tune

 

Steve, do your extenders have a reduced opening at the bottom?

 

One of my previous cars was Evo VIII. The fix was to just drill out a spark non-fowler. Very inexpensive and available at NAPA. If one wasn't sufficient then use 2 to extend the length. I believe the threads will be the same...

Another option was to install an O2 simulator / eliminator. This just produces the correct voltage for a clean O2 reading - no tune required.

Here is the thread from the Evo boys:

http://forums.evolutionm.net/evo-how...cel-light.html

 

Here is what I will use, extenders with restrictors...

 

Thanks for the continued information on this thread. The 'kit' showed above by ebspeed would seem to allow you to tinker a bit to strike the right balance, which might be nice to have. It's always good to have options, and several have been presented here. Thanks all.