CEL gutted cat???

**fastlt1** · 09-16-2009, 07:44 AM

My brothers in laws decided to gut my mother in laws cat. And guess what she it getting the CEL. It is a 98 305 k1500 5 spd. Is the CEL messing anything up? Will it hurt anything? Some says it means nothing and does nothing. Some says it hurts gas mileage. Some says it could dump enough fuel to foul plugs and the other o2 sensors. Thanks.

**SolMan98** · 09-16-2009, 07:47 AM

Well you already know why you got the CEL.

You have a couple of choices, replace the cat is the legal and smart thing to do IMO. You can get a custom tune to turn off the rear 02's or get sim's for the rear 02's.

Yes it can affect mileage, the 02's are telling your PCM that you don't have cats and it's trying to readjust your fuel, timing, etc to get back in range. But it can't.

**fastlt1** · 09-16-2009, 07:49 AM

But is it hurting anything running with the CEL?

**SolMan98** · 09-16-2009, 07:52 AM

Originally Posted by fastlt1

But is it hurting anything running with the CEL?

It can and will damage the rear 02 sensor along with other sensors.

**loweredchevy5.3** · 09-16-2009, 08:45 AM

All the rear o2 sensor is doing is telling the computer I you have a working cat the front one is the one telling it to give it gas and the rear ones don't do nothing but see if the cat is working. No the cel will not hurt anything but get on your nerves but you can get it tuned and turn the rear sensors off and you will be fine.

**SolMan98** · 09-16-2009, 08:48 AM

Originally Posted by loweredchevy5.3

All the rear o2 sensor is doing is telling the computer I you have a working cat the front one is the one telling it to give it gas and the rear ones don't do nothing but see if the cat is working. No the cel will not hurt anything but get on your nerves but you can get it tuned and turn the rear sensors off and you will be fine.

If it's running too rich, which it probably is, it will prematurely cause the 02's, pre and post, to go bad if nothing is done about it.

**loweredchevy5.3** · 09-16-2009, 09:38 AM

It's not going to run any richer unless he pulled the 1st sensor out but all the rear is doing is saying that the cat is working or not and in his case it's not so he can get it tuned and delete the rear sensors and they won't register and the cel will go off. It may smell richer but is just not haveing the cat burn the extra fuel. I've done this to 3 of my trucks and never had any problems what so ever.