Cat delete
 

So previous owner removed the cats from my 1990 suburban because of this while driving on the highway or for longer periods of time the o2 sensor sets off the check engine light. Kinda annoying. Is there a way to bypass this without putting cats back on the truck

Re: Cat delete
 

Why not have some cheap high flow ones put back on it?

Re: Cat delete
 

^ high flow ones are pretty much a straight pipe with a cage around it. Looks like a cat but isn't.inspector is happy for the looks and you're happy for the performance... Win win!!

Re: Cat delete
 

Electrical tape over the Check Engine light...

Re: Cat delete
 

Maybe try a heated 3 wire 02 sensor. You run the extra 2 wires to keyed power and ground. I use one with headers and no cats and the check engine light doesn't come on.

Re: Cat delete
 

I've never had cats on my 91 and its never had a CEL...

Re: Cat delete
 

How did you come to the conclusion that your lack of cats is causing the O2 sensor reading to trip the CEL?

Are you sure the issue isn't the 02 sensor itself?

Since the 02 sensors are upstream of the cat in these trucks, the lack of a cat should have little to no bearing on the readings the 02 sensor is sending to the ECM.

Re: Cat delete
 

Agreed, single O2 systems have no knowledge of the catalytic converter being gone. '96 and later GM's had two sets of O2's, one ahead and one behind the cat, and the comparision of the downstream cat to the upstream one and those can see when a cat is missing.

Re: Cat delete
 

Me neither! The O2 is before the cat on these old trucks so the ECM will not care, or even know, if there is a CAT present or not. I agree with Zane, something else is going on.

It is a Federal Crime to remove the cats but it is okay to use a “test pipe”. I’ve been testing this “Test Pipe" for a few years on my ’89 Burb and so far the “test” is going well. I think I will keep “testing” it for a while longer. ;) The CEL has never come on either.

“Test pipe” viewable on the far left
http://farm9.staticflickr.com/8357/8...765f5ed6_c.jpg