Cat removal on '01 Chevy K1500

[Patriot_RAM]

Hey Guys,



I have an '01 Suburban K1500 that has dual cat's. I need to remove these, but need help answering one question. There is a sensor in front of the cat, and another behind it. I'm assuming the one behind it will throw codes of some sort if the cat's are removed.



Can somebody tell me what the sensor after each cat is and how I can successfully bypass it's logic to remove the cat's without throwing codes?



And yes, let's assume this is for off-road use only. :-laf



Thanks!

 

[Dl5treez]

The sensor after the cats is the "Catalyst Efficiency" Sensor.

The pre-cat O2 sensor is what the engine control module uses to calculate rich/lean fuel mixture/spark timing adjustments.

The post-cat O2 sensor is purely there to monitor how well the cat is doing it's job... . and also to take away the option of permanent removal.

It's looking for zero oxygen in the exhaust stream. pre-cat voltage outputs flucuate from 0 to 1 volt... . zero volts being lean, 1v being rich.

The post-cat sensor should read a steady . 8-. 9 volts. Any change from that, or if it shows an identical reading to the pre-cat sensors, tells the ECM there is oxygen in the exhaust stream, and possibly unburned fuel, and that the cat is either A) not up to snuff or B) not there at all.

If you take the cats off to put test pipes in, you'll set a code for Catalyst Efficiency Monitor Out of Range when the engine hits closed loop (operating temperature). The only bypass is to seal the sensors up inside a pipe full of inert gas. . nitrogen for example. Then they'll always read zero oxygen and you should be fine... of course the logistics of actually getting this modification performed are about like floating the Titanic, so best of luck to ya.

The SES light will stay on until it's cleared and keep returning until the cats go back on. You can thank the EPA for that.

But, the truck will still run just dandy enough to rule out a plugged converter, if that's what you're searching for. It's an emissions code and IIRC it won't affect the engine's operating parameters. No guarantees though.
Hope this helps,

Dan C.