Introduce myself and a couple??

[cbrown228]

Hello ladies and gents, First off, I wanted to say how much I've enjoyed and learned from this forum!! I recently purchased a 2008 G37S. It has a K&N Typhoon intake installed but (as far as I can tell) a stock exhaust and I do not know if it was tuned properly. My SES light has come on twice. (After I ran it pretty hard each time) I had the code read as P0420 "Catalyst System Efficiency Below Threshold Bank 1". Also, I noticed a "metal weaved ball" (not sure what it's called) on each side of the exhaust. Both "balls" have damaged on the underside, tearing part of the weaved ball open. Here's my questions, Is there a way to see if the engine has been tuned or is it best to tune it anyway? Would the damage to the "weaved balls" create problems? and Are they easy to replace? Would any of these issues create my code? Any help would be appreciated! Thanks in advance.

[audtatious]

Could be a sensor or leak. Troubleshooting steps start on page EC-272 on the below link

http://www.nicoclub.com/FSM/G37/Coupe/2008/EC.pdf

The weaved balls are probably the exhaust flex sections and if they are damaged then they could be leaking and causing the SES. AFAIK there is no way to determine if you are running a non-factory tune.

[kmckis1029]

+1

a exhaust leak or a bad sensor...

Is the car runny test pipes? (non-stock cats) that could cause a SES too.