I own an orange 2007 RS.1. I have a Sharkwerks rear exhaust bypass, otherwise box stock. 15,400 miles. Plugs never replaced, air filter brand new (old filter fine). Street driven only. Perfect overrev history. I am observing one side (drivers) white and dry in color, the other sooty dark. My dealers "reader" is broken, awaiting replacement unit from Germany. Tech says "fuel trim" related. Questions: Are there adjustments for each side independent of the other side for fuel trim (mixture?)? Any other ideas what could be causing this? Thanks in advance for your learned and insightful advise.

 

Yes the car can trim fueling side to side based on the oxygen sensor readings. If you're seeing really rich on one side and fine on the other, I would check a few things:
1. Vacuum leak on the sooty side, metered air is escaping and the car is over fueling that side (should be a code to eventually pop up I would think over the MAF and O2 sensor not agreeing on fueling)
2. O2 sensor needs to be replaced
3. Exhaust leak sucking air into the side that is sooty making the O2 read a bit artificially lean...

Could be a bunch of other items as well, surprised there isn't a code coming along with this...

 

I have watched others start mine and I see white smoke in one and clear out the other. Never gave it much thought though.

 

Thank you both for your information. O2 sensor makes a lot of sense, and they are notorious for causing problems. No codes as of yet, although the idle is a hair lumpy. Thanks again.

 

My idle is lumpy as well, but I have black tips, so hard to see soot!

Good luck!

 

Any thoughts as to whether pre-cat versus post-cat O2 sensor would be the culprit? Can they be checked with a VOM, or do they need to be fancy Porsche scanner scanned?

 

pre cat are the feedback for Short term fuel trims (active fueling management) Post cats have some influence on long term fuel trims.
Not sure what VOM is... If you have a program like PWIS or equivalent you'll be able to see the actual lambda readings from the O2 sensors as well as Fuel Trims...

With an OBDII reader for your phone should be able to see fuel trims as well...

 

pre cat only. After cat are for emission purposes.

 

Yup, and tweaking with the voltage can give you a nice wideband meter.

 

Please expand on this...

 

Beer time in Greece......

 

lol Peter ! shudup..

Under the circumstances, I'm changing camps and keep on projecting myself on turbo stuff.

I'll expand tomorrow.

 

Ah, you speak Eddie language.
He can hardly keep himself from stealing my car to start messing with the tune.

 

it will happen soon, don't worry

only data will tell

 

Jamie_GT3, the VOM refers to a volt ohm meter. I was wondering if I could check the resistance through the sensor, and if that would tell me anything? I do have an OBDII reader - are you saying that is sufficient to diagnose the situation with the O2 sensors? Thanks much for the help.