O2 sensor

[Leff]

So I finally got around to throwing some LTHs on the truck. Ran wonderfully for about 50 miles but once it started cooling off the CEL came on for the O2 sensors. Has anyone found a good way to get rid of the light besides tuning it?

 

[stevj]

Don't know what is a LTH, so can't answer that one.
Since you know it's an O2 sensor, which bank (1 or 2) and which sensor (1 or 2)?
The upstream sensor (no 1) is before the catalytic converter and close to the exhaust manifold to provide feedback to the ECU, keeping the air/fuel mixture correct for driving conditions.
The downstream sensor (no 2) is there to measure efficiency of the catalytic converter.

Steve

 

[Richard320]

I'd start by looking for air leaks. Remember, O2 sensors don't read rich/lean, they read oxygen content.

If you have a mechanic's stethoscope, remove the probe and shove a ballpoint pen tube (or anything else that fits that is handy) in the hose and run that around suspicious areas. The slightest air leak will be amplified massively and the narrow opening lets you pinpoint it.

 

[UnloosedChewtoy]

So I finally got around to throwing some LTHs on the truck.

Don't know what is a LTH, so can't answer that one.

Long tube headers most likely. In my short experience with them in previous trucks, 99% of the time, you need to do a tune to get it to run properly (and without CEL).

 

[Mountain Whiskey]

Check for any little leak ahead of it as it will throw a code.

I didn't know a tune would be needed. Have to unlock the pcm for that.

 

[Orion10182011]

If it's the downstream O2's you might try O2 spacers. This works with cat below spec codes.

If it's the upstream, your going to need a tune. LTH's move the location of the O2 farther down which must be compensated for in the tune.(on GM LSx engines anyway)