ebbjak

2001 Boxster S, 39,000 miles.  I've been battling with a P0133 code for a few weeks, it indicates a slow O2 Sensor Bank1 sensor 1.  I've replaced both pre cat O2 Sensors and the code came back after resetting.  I've pulled fuel trim data and it is unremarkable, both Long term and short term.  The data does show a slow O2 Sensor bank 1 sensor 1, but both are new.  So I swapped sides of the new O2 sensors hoping that the issue would switch to bank2....It did not!  :angry:  So, I'm out of ideas.  Thoughts?

Yes, Bosch 15182.

Thanks for the heads up about the change.  If the light returns, I'll swap the sensors and see if the plots follow.  Both sensors are new, so other than a bad O2 sensor, what would cause it to be slower?  

I couldn't figure out how to plot what you were asking for so hopefully the pictures below will make sense.  I have reset the light today but have only put about 10 miles on since resetting.  The next couple of days my schedule will not allow me to get the car out to further test.  Also, both pre car sensors are brand new from Pelican Parts so I would guess it would be odd if they were both bad.

First of all, thank  you for all of your help.  I've had my car for 10 years and I've never had any issues with it, so I've still got a lot to learn.  I ran the STFT and as one might expect, it varied pretty dramatically.  The highest values were about 5.7, however almost right after that it dropped to -5.7 (Bank 1).  Bank 2 was similar.  The number that came in most often was .78 for bothbanks. 

The number most often displaying was .78 for both banks.  My guess is that the numbers look relatively normal. 

When I ran the LTFT numbers yesterday they were flat and both about .73

And the engine was warm but it wasn't being driven.

I'll need to run both trim levels tomorrow.  This is the trim level from bank 1

How's This?

If you have an Android phone, get a $15 Bluetooth OBDII dongle and the Torque Pro app and you can plot graphs like these

http://rennlist.com/forums/996-forum/810606-obd-ii-code-reader-recommendation-2.html#post11299728

If you have an iPhone, get the wifi OBDII dongle. I'm not familiar with iOS apps but I know they have something very similar.

The above assumes you don't want to invest in Durametric, which is the best and most comprehensive for DIYers.

 

I ordered  the dongle today. I'll measure the O2 sensor readings early next week and report back. Thanks for the tips!  I didn't find any leaks in the air intake by the MAF, but I tightened all of the clamps and verified all of the connections to ensure they are snug.  I reset the CEL and will check the O2 readings when the Dongle arrives.

 

 

Sorry.  You're right I should have included year.  It's a 2001 Boxster S, 38000 miles.  I will check the air intake after the MAF, thanks for the tip.  I don't currently have access to the Duramatic but I do have a smartphone, but how would that help? 

So I looked up the codes and based upon my findings, I replaced both pre-cat O2 sensors.  In addition, I cleaned the MAF.  I cleared the codes and after about 30 miles the CEL came back on.  Same code.  What's up with that?  Is it possible a new O2 sensor is bad?