Ok on my 2004 I have 3 O2 sims. Two infront of each cat and one right after they merge into the y pipe. So if I take the cats off which SIMS to I need to replace. just the back one or all three.

 

I'm lost... to me sims= simulator, unless this is high level GM geek speak.

So my interpretation is that you have 3 O2 sensors on your truck, two before your catalytics, and one after. correct?

Your asking where you should put in the O2 simulators so that you do not get a check engine light on your vehicle. Generally speaking they go on the narrow band sensors or the 1/2 wire ones(normally rear). Never touch the wideband 4/5 wire widenband sensors.

 

ok so I would only need one. People tell me all the time I am confusing when I talk. My brain goes alot faster then my mouth and my typing is twice as slow. thanx for the info.

 

Are you sure your looking right? Im pretty sure there are 4 O2 sensors. Two in front and Two behind. The O2 sims should go in the place of the rear O2 sensors. Then you can remove your cats without a SES light.

 

I thought their would be two behind but I only gave a quick look. I will look again tonight and see if their are two or one. Also what kind of sound can I expect from deleting the cats. It's not loud enough right now. But it's clean sounding.

 

Your in for a shock with no cats. Yea it will get a little louder, and alot meaner. Mine sounded totaly different.

 

that's waht I am hopping for. Dang I have only had my exhaust for a week and I already want to make it louder.

 

You need to study OBD II so you can get a grasp on what the pre cat 02s and post cat 02s do so you'll know what your doing and why your doing it. You don't have to remove the cats. The cat shells are still there, but they're hollow. I gutted mine with a plumbers snake chucked up in my electric drill. It will sound even better if you install a cam with a 112 LSA and some headers and dual cat back. That's why I did and it sounds great.

 

I took my cats off last weekend and it is pretty loud... I'm loving it..

1 question though if I drive around with the check engine light on from not having the sims is it gonna hurt the performance of the motor? like messwith timing or something?

 

Anybody know where to get the 02 sims i need 2 of themmmmmmmmmmmmmmm