problem: slow O2 sensor response with headers installed.
I had a good tune, street cam/head setup and long tube headers with high flow cats. I ran with the PO133, PO153 codes for a year and a half. New O2 sensors (Bosch 13111) did not fix it. My O2 heater circuit was working and fuse was never blown. Checked all relative ground connection (they looked great). No exhaust leaks.
I did not want to spend time revising the tune to fix this and I was due for the NJ inspection.
Heres what worked for me.
If you examine the bosch 13111 O2 sensor it has 3 very small slots in the protective cover over the sensor. These slots are how the exhaust reaches the sensor. Someone had reported better results with Denso O2's. I noticed that they had small holes in the cover instead of these small slots.
I drilled 6 small holes about 0.10 dia. in pairs, in the protective cover between the slots. See pics You must not drill to deep and damage the sensor. I used a drill press, set the stop on it and just broke thru the protective cover.
Installed the new modded sensors and all is good.
Cleared the computer, ran thru the GM computer ready requirements and I have not had a code or drivability issue since (approx. 500 miles to date).
I don't know how long the sensors will last. But I am good for two years or until I make a new major mod (or the sensor dies).
Give it a try

 

Excellent mod and a good observation on your part. By drilling the holes you've exposed more of the elements to the exhaust gas. They may not last as long but hey, it's better than getting sensor codes especially since you have to pass smog inspection. What kind of headers do you have on your car? It seems that the long tubes like kooks, dynatechs and LG's cause more of these problems than some of the other makes.

 

I have LG's headers. I did run the car with the head and cam for one year without the headers. I had gutted the pup-cats and ran with the original O2 sensors and factory cats in their factory location with no problems.
The header bung may shield some of the O2. The problem most likely is due to cooled exhaust by the time it reaches the sensor.
The headers are doing their job. They are moving the exhaust but disipating the heat with all of the surface area.
I will be putting the car away for the winter. It will be some time before I know how long they last.

 

It'd be very interesting to monitor those O2 signals to see how that's affected the A/F they are reporting with the new holes.

 

Hi Mr. Jones -

Cool - good idea!

I just had mine tuned out to ignore the slow response messages.

Please let us all know how this impacts the life of the sensors.

best regards -

mqqn

 

NJ allows one not ready on their emissions inspection. I had the rear O2 sensors deleted. Thats one not ready in the test. If your state does the same test and you have the rear O2 sensors deleted (I don't know if you do) you will have two not readies show up in the test. You will have eliminated the DIC light but you will still fail the test.