O2 sensors on LT's
Thread Starter
Instructor
Joined: Aug 2008
Posts: 204
Likes: 0
From: Lake Placid Florida
O2 sensors on LT's
I'm about to install my LT headers. I have read that some move the rear O2 sensors to the front and plug the rear bungs, then have them tuned out. Is that the way to do it ? Why ? What does that do ? I know they can't be crossed, I'm sure that's left for right, but, why this ? 
Burning Brakes
Joined: Jul 2004
Posts: 1,172
Likes: 71
From: MA
It depends on your headers. On AR headers you don't need to swap the backs to the front because the headers are a bit shorter than longer tube designs such as LG and Dynatech. The reason that the longer tube designs need the back O2s moved to the fronts is because their O2 bungs are much further back and thus run cooler. The rear O2s have better heaters than the fronts
I ceramic coated my headers and kept my secondary air system. I think this, combined with the shorter tube design of the ARs help. I also have my rear O2s in place and haven't tuned them out. So far, I don't have any codes!
I ceramic coated my headers and kept my secondary air system. I think this, combined with the shorter tube design of the ARs help. I also have my rear O2s in place and haven't tuned them out. So far, I don't have any codes!
Drifting
Joined: May 2005
Posts: 1,590
Likes: 1
From: Littleton Colorado
The rears do cross, left side plugs into the right side. It will make more sense when you are under the car. The rears don't really matter that much because they only report if your cats go bad, they are not involved in fueling like the fronts are.
Where it does become an issue for some brands of headers is the front sensors, the location of the bungs can cause you to cross the fronts, and that is a big deal. If you cross the fronts it will run really rough because the PCM is trying to adjust the fuel mix and its getting the wrong data so it can not see the effects of adding fuel. This happens a LOT.
A lot of people do delete the rears because they only report on the condition of your cats. Its up to you if that is good or not.
For my set of headers I had to use the rears in the front because the old front ones would not reach to the bungs on the LT headers.
Be aware that if you do need to use the rears on the front that you will need an adapter because the connectors are different. You could also look into extensions for the old fronts, but finding the right length might be a challenge.
Where it does become an issue for some brands of headers is the front sensors, the location of the bungs can cause you to cross the fronts, and that is a big deal. If you cross the fronts it will run really rough because the PCM is trying to adjust the fuel mix and its getting the wrong data so it can not see the effects of adding fuel. This happens a LOT.
A lot of people do delete the rears because they only report on the condition of your cats. Its up to you if that is good or not.
For my set of headers I had to use the rears in the front because the old front ones would not reach to the bungs on the LT headers.
Be aware that if you do need to use the rears on the front that you will need an adapter because the connectors are different. You could also look into extensions for the old fronts, but finding the right length might be a challenge.
