I have a 2006 Cayman S build date is 11/05 and currently have ~6000 miles on it. The CEL problems first appeared about the same time I started running 100 octane fuel. At first it would go on and by the time I was finished with that tank of gas it would turn off on its own. I was actually on my way over to the dealership to have it checked and low and behold it turns off on the way over. They said there was no record of the faults and was probably from not tightening the gas cap all the way.(This was 2 months ago) So I was like OK whatever. Same problem kept on happening and the CEL would eventually turn itself off. Now it stays on until its cleared and will re-appear within 3-4 ignition cycles. I don't have the exact fault codes right now, but I keep getting the same 4 codes over and over for low threshold catalyst faults both sides.

So my real question is....Should I just get the Softronic flash and not worry about it or should I have the dealership troubleshoot it. The second issue is I installed a Cat-Back about a week ago (Remus) and I know the dealership will blame any problems found on the catback since I did not have them install it.

So before I go thru the trouble to put it back to stock is there any helpful info one of you caymanclubers might have for me

Thanks hopefully that makes sense

It sounds like your first set of cats is the problem... many of the early build '06 cars had to have their cats replaced becasue of failures.


If you're going to have the dealer troubleshoot it, you would be wise to have the exhaust system returned to stock - but you might try taking it in first to see - the folks at Gaudin seem to be fairly mod-friendly, and if it's the first set of cats, or otherwise something upstream from the aftermarket system, they should be able to tell.

You don't mention if you have changed the DMEs software on your car to something like GIAC or Softronic to take advantage of the 100 octane you are using. If not, then you are wasting a substantial amount of money running straight 100 octane racing gas in your car. The stock DME is optimized for 93 octane, so any more than that, doesn't change a thing unless the software is changes to accommodate higher octane. I realize that 100 octane is available at a lot of the Rebel stations around town - if you want to boost the normal 91 octane premium, the best thing to do is to put about 3 gals of 100 in the tank, then fill the rest of the tank with 91 octane - that will get you the 93 octane the motor and software can take advantage of... anything more than 93 is a waste of your money.

brad

__________________
21-year PCA Member
PCA DE Instructor

I agree with Brad. If you haven't reflashed your DME, it can't burn all the 100 octane fuel before the exhaust valve opens (higher octane burns slower) hence you are dumping unburned fuel into the cat. You will burn the cal out this way, and it will give you a CEL!

Greg

If that 100 octane race gas is LEADED you have just coated the media inside of the catalytic converters and maybe poisoned the O2 sensor as well, these conditions will cause a CEL.

All the 100 octane gas available here is unleaded... so this isn't a factor.

brad

__________________
21-year PCA Member
PCA DE Instructor