Fouling of Oxygen Sensors...
 

I have been talking with a couple of forum members about our modded cars fouling their oxygen sensors and giving us 1133 and 1153 DTC codes (O2 switching test failure--either bank).

The theory is that...
having long tube headers (sensors are farther downstream, thus less heat to the sensor),
a healthy cam (longer duration and/or narrower LSA allowing excess fuel into the exhaust at lower RPMs),
a relatively typical re-tune (runs a little too rich at idle and lower RPMs),
and an older LS1/6 engine that may be inclined to burn some oil now and then...
are causing the oxygen sensors to foul without the ability to burn off enough of these contaminates, eventually leading to one bank's switching test failure, then the other bank shortly there after.

Has anyone else had these issues, with similar mods? Have you solved them?
Can someone pinpoint the exact source of the fouling, or is it a definite combination of the above scenario?
Will a particular aftermarket oxygen sensor help solve this? Or is the key to this in the tune?
I have been told more timing, but with less fuel at idle, may help. Some have heard of drilling additional holes in the oxygen sensor?
Or does a guy need new rings/fresh bore/new valve guides?

Any input would be great! Thanks, Joel.

Well I got a code for the rear O2s because you are correct that they are futher back, so my tuner turned the rear O2s off. I now and again get a code for the right front O2 and all I do is clear it and it stays away for awhile.
Someone else will chime in with a better answer.

If the o2's are good, the tune is good/close and you have headers and your getting a slow response code the drilling should work.
use a drill stop and just break thru the cover.
The sensor inside will not take any abuse
This is how I fixed my 02 slow response.
had my tune checked, tried new bosch 02's nothing worked until I drilled them.

http://img.photobucket.com/albums/v2...sor/o22939.jpg
http://img.photobucket.com/albums/v2...sor/o22938.jpg

I and many others have had this same problem. We've all had my tuner turn off the "check" light associated with the issue as our tunes are perfect. My tuner only charges us $50 to complete this. If you want his info PM me or email me.......

Thanks guys!
Jonesy--Great pics, I might try that.

I will also talk to my tuner about loop status and turning off the CHECK ENGINE light in this situation. I may email you guys on the specifics of your combos and symptoms--Thanks again!

Any other experiences, any possible fixes (simple or otherwise)?

Thanks, Joel.

Since it is the job of the 02s to control the AFR I doubt that living with the bad readings or turning off the DIC code is consistent with proper AFR.

your tuner can turn off the rear o2's not the front ones.
your computer will show it as not ready.
this is not a problem for those of us that have inspections where they plug in. there are also no drivability issues with turning off the rear o2's.

there are no driving issues with the front o2's if the only code is slow response.

The P1133/P1153 codes for insufficient bank switching are due to the placement of the sensors in the longtubes. More or less, the computer thinks that there should be a "pulse" of exhaust causing a spike in the 02 voltage at a specific time. Large overlap cams, or even just the collectors of the longtubes can make this pulse alot weaker, making the computer thing that the 02 sensor is not working propperly. You can edit the tune to remove those codes and still pass the OBD2 scan test for emissions if it's done properly.

Thanks guys! I will get with my tuner and see if he wants to consider one or two of these angles. Sounds like it is fairly typical of "LT header and cam" cars. I guess I will put the $6k L92 build-up on hold for now :D .

Thanks again, Joel.

Happy to hear I'm not the only one having this occur now and then - I've never heard of "drilling" the O2 sensors though, so that is good info

QUESTION: does drilling the O2 sensors eliminate the P1133 and P1153 code intermittent appearance?:bigears

I get one of those codes everytime I drive my car. I reset it while driving. I would like to fix it permanently though. Just headers here. If placement is the issue then a specific brand or style would be causing this correct? I have TPIS with no cam and tune. I will talk to my tuner when I get a chance as well. Good luck all.

ill bite too
 

Iam also curious as to whether or not the drilling gets rid of the pesky slow bank switching codes as I have these pop up from time to time also with just my LG headers.

Does having the headers coated or not affect these symptons? Just checking to see if less people with coated headers or a particular brand are affected. :cheers:

The outer housing on the "new" AC Delco's is perforated and work great!!

JR