Originally Posted by [ion] C2 (Post 401336)

Had my header put on today at Midas, helped 'em install it. Rearranged my cat and such too, so that now things are:

header --> downpipe --> flexpipe --> cat --> magnaflow --> piping --> dynomax --> outlets

My primary O2 sensor looks terrible, like it exploded. The shroud around the sensor is frayed to hell, and the center part is like white, like it experienced super lean conditions, and it's also flaking apart:



This is how it's supposed to look, I think:


It seems to have worked fine before I had the header put on... my AFRs were decent in closed loop, stuck somewhat near the commanded. I did notice lately when I tuned the AFR % error was pretty high though.

Header
The header is a Pacesetter made for the Cavalier with EGR. I used a new 2000+ non-EGR gasket.

Primary O2
The header's O2 bung in the collector did not leave enough room for the primary O2 to be installed, so that hole was plugged and the primary O2 was installed in a new bung welded very close to the collector. The wires were also extended using some sort of butt splices that include heat shrink wrapping, the gauge of the wire was the same as the stock wires.

Secondary O2
The O2 after the cat was removed, as far as I know it is irrelevant. My catalyst code has been turned off, and I figure the secondary O2 cannot detrimentally affect performance in any way whatsoever.

Wideband O2
The wideband O2 sensor is just behind the primary O2.

The engine idles quite rough at idle now. I noticed it seems to swing to lean quite a bit at idle now as well. The header collector flange to the downpipe flange is a ball joint. I think it is possible that it leaks. If it leaks, it's before the primary O2 which would give it skewed readings, I'd think.

What the hell would cause this problem? Could it be that the primary O2 sensor is just garbage, and if I replaced it, would solve things? I've had a feeling my primary O2 has been going for a while.. also, my fuel economy seems to suck lately.

Rough idle... PE running doesn't seem to be affected (open loop)... fuel economy drops... bad O2?

Originally Posted by adam337 (Post 401484)

awe cmon mang. :[

Originally Posted by adam337 (Post 401479)

wanna talk about looking sexy? i just got out of the shower and im only wearing a towel. now THATS sexy.

Originally Posted by [ion] C2 (Post 401402)

Good job quoting it all.

It's definitely an O2 sensor. I just read another report of someone else's experiences and it can cause long and hard shifting, which is what I've been experiencing lately. Along with a 35%ish drop in fuel economy, as others reported.

Originally Posted by KenshinZero (Post 401519)