I have obx headers and have yet to install because I have to do emissions and I heard headers make you fail but can I pass if I get o2 sims and what exactly are they for anyway

 

They pretty much trick the computer into thinking everything is A OK. You can't use sims for primary, which regulate fuel/air, etc, but the secondary O2's don't do much. The sims will prevent the CEL from coming on which pretty much will fail a inspection immediatly. The secondaries O2's are only operable when the vehicle is cold anyways.

 

[quote=VQP0WER;7884836]the secondary O2's don't do much.quote]

so what's the exact role of 2ndary O2 sensors ? would they affect performance if they are bad ?

 

[QUOTE=mahanddeem;7885148]The sims only make the computer think the precats are doing their job removing pollutants from the exhaust, just like the secondary O2 sensors do. Even if the secondary O2 sensors are bad, the only affect is the SES light.

 

Does this work for anyone??? It's O2 sensor extender, for tricking rear O2.
http://cgi.ebay.com/ebaymotors/O2-ex...Q5fCarQ5fParts

 

In Calif you can fail emissions if the tech just looks under the hood and sees headers.

 

You could probably use an Anti-Fouler and take the SES light off.

All the second o2 sensor does is see if the exhaust gas is cleaner after it goes through the cat. If there are no changes in the condition of the gasses getting better, than it sets of a Pre-cat failure

 

I have obx header and simm. No CEL so far!

 

wont help you pass emissions, it just basically tricks the computer into thinking the the exhaust gas has been cleaned by the cats. I would install after the emissions test, if you have surging with acceleration the o2 sims will work good for that because the ecu using the o2 signals to determine what the air/fuel mixture will be.