My D1 has had the cats removed...Meow !

Anyway.. It's giving codes for the front O2 sensors... I need to check the wiring and such before just replacing them..

Is the computer going to be OK with the cats being removed ?

Just wondering what that does since it's looking for a difference between the upstream and downstream sensors...

Thanks.

John

 

The O2 sensor monitoring determines closed loop fueling, so you could be in for lower mpg (yes, it can get worse).

The car guys at the track have used small modules that pretend to be an O2 sensor, to fool their computers (and the state inspections, but that is illegal in some states, and you truck will be impounded by the EPA and crushed before you in the public square, and you will be forced to drive a stripped down Yugo with no glass or bumpers for a period of not less than ten years or more than 50 years.)

See O2 Sensor Simulator for one source.

 

As long as your upstream sensors are working, removing the CATs should have no effect other than making it louder and maybe popping an emissions code. The downstream sensors are only used for emissions testing, not fueling. They can be disconnected.

 

Like Savannah says, this is illegal if you have emissions inspections in your area.

That said:

How To: Install An O2 Sensor Non Fouler to Eliminate a Check Engine Light with Pics - Chevrolet Colorado & GMC Canyon Forum

(This is for the downstream sensors, btw. The ones after the cat.)

 

I'm going to be doing this to my truck too soon.
After 220,000 miles the guts are starting to fall apart.
Did you weld in straight pipe or what?

 

That's what I did. Dropped the y-pipe. Cut cats off. Sold them for $80 each. Reinstalled y-pipe. Cut straight pipe to length. Tack welded in place. Dropped y-pipe again and smooth welded. Reinstalled y-pipe.

 

Eric did you use the non fouler's for your rear O2's or are you just living with the CEL?

 

FWIW on the "no cat" codes.....back when my ecu got wet and started causing misfires, I ended up damaging a fairly new cat....and started getting cel codes for the cat being out of spec. I couldnt find the right non-foulers anywhere local....ended up making these from a reccomendation elsewhere on the net.....all threads need to be 12mm x 1.25.....easy install & no codes,( just untill I can afford to replace the y-pipe again of course)

 

That little CEL bulb is easy to remove. I use an ultragauge to monitor. Much more informative than a light.

 

Very good point, set your alarm for new codes, remove the CEL bulb and dont worry about it.
I like that.