Cat delete and O2 sensor work around?

[HeliMatt]

Hi all,
I have a 96' yukon and I'm thinking about deleting the catalytic converters with a custom exhaust. My question is has anyone done a cat delete, will that affect the upstream O2 sensors, and is there a way to work around the downstream O2 sensors throwing a code? I've seen the spark plug anti-fouler method. Has anyone tried that and does that work, or is it better to tune them out?

 

[Eman85]

My cats are long gone on my 98 K2500 and the O2 sensors are all still there, no codes ever set. Didn't do anything to it, your results may vary.

 

[5StarCustmSolutns]

Currently deploying the anti-fouling method on the downstream sensors in my 2011. Did it to try and fix rich condition caused by incorrect algorithm calculation of the fuel alcohol percentage (FA%). It helped bring the LTFT's up a little closer to normal. But eventually bought HPTuners and set FA% maximum allowed to 6 or 7%. (neither one truly fixed my problem) But re: your application, the anti-fouling cups do reduce the amount of exhaust gas the sensor is exposed to. per common sense: the larger the hole the more exhaust gas will reach the sensor

 

[Fless]

Currently deploying the anti-fouling method on the downstream sensors in my 2011. Did it to try and fix rich condition caused by incorrect algorithm calculation of the fuel alcohol percentage (FA%). It helped bring the LTFT's up a little closer to normal. But eventually bought HPTuners and set FA% maximum allowed to 6 or 7%. (neither one truly fixed my problem) But re: your application, the anti-fouling cups do reduce the amount of exhaust gas the sensor is exposed to. per common sense: the larger the hole the more exhaust gas will reach the sensor

You're probably past this, but for other readers I believe that GM issued an updated calibration (firmware) to correct the over-calculation of alcohol percentage.

 

[Trey Hardy]

Hi all,
I have a 96' yukon and I'm thinking about deleting the catalytic converters with a custom exhaust. My question is has anyone done a cat delete, will that affect the upstream O2 sensors, and is there a way to work around the downstream O2 sensors throwing a code? I've seen the spark plug anti-fouler method. Has anyone tried that and does that work, or is it better to tune them out?

My uncles 96 has no cats and he never had any issues same with my 93 I never had no cats and never had any issues on the newer vortec motors I think you can tune the rear 02s out all together and delete them that’s what I’ve always done with my LS engines when I put Longtubes on em

 

[Marky Dissod]

I have a 96' yukon and I'm thinking about deleting the catalytic converters with a custom exhaust.
My question is has anyone done a cat delete, will that affect the upstream O2 sensors?
Is there a way to work around the downstream O2 sensors throwing a code? I've seen the spark plug anti-fouler method.
Has anyone tried that and does that work? or is it better to tune them out?

Best, most permanent solution is to tune pcm to ignore rear O2s.
Deleting the catalytic converters does not affect the pre-cat O2s.

 

[5StarCustmSolutns]

You're probably past this, but for other readers I believe that GM issued an updated calibration (firmware) to correct the over-calculation of alcohol percentage.

thank you.....have not gone in for that. mainly because, well, I guess I want to know why it started happening? miles and miles perfect then one day, out of nowhere, not perfect lol...
I honestly don't know but I lean towards one of the 7 or 8 sensors that provide the data for the algorithm changed what it was sending, basically overnight? I can't wrap my head around how else it could start over-calculating? that is: assuming the transponder in the black(silver) box behind the head unit is NOT bi-directional? -and- assuming the code for the algorithm was NOT written to intentionally change the formula at a certain age/mileage?? If the only fix GM is offering is done with a keyboard, then I may have fixed it myself w/HP Tune by reducing the maximum allowable FA% from 100% > 6%??

I don't want to distract from this post... But would love to hear any other thoughts on the subject over on the thread linked at bottom
*****@Fless you and I have discussed this before lol, I originally asked you to DM me and then thought to go get the link and when I did I saw one of your replies! thank you*****

Persistent P0420 and P0430

If this is about the 2011 truck in your signature, it has NO physical flex fuel sensor unless someone added one. It's all done by the PCM/ECM calculations. If you know for certain that the actual alcohol percentage is low, reset the long term fuel trims and reset the alcohol percentage. Is...

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