DTN

^^ AHA!!! Just as I suspected. High flow cats are not for our cars. It was meant for much more exhaust to go through it. It's not heating up enough. Our cars stock catalytic converters are not cali compliant. The cali compliant ones have a 2nd catalytic converter after the last o2 sensor.

http://shop.ebay.com/items/?_nkw=o2+sensor...r&_osacat=0

The one I have has alot more threads on it, and all but a small 1/4" hole is covered on the tip of it. These should work fine though.

BTW.... with this extender I have, the readings from the 2nd o2 sensor look the same. It fluctuates up and down just as the stock (non extended sensor) did. I don't notice any difference in the waveforms from my obd-II readings.

HyundaiKitCoupe

excellent info i8acobra!! right on DTN. it's not heating up enough because it was designed for a lot of exhaust to heat it up quick. but if the spacers work then be it, nothing is changing really.

alrighty. you can patch that hole up with some welding compound.

DTN

The hole is to let some exhaust from the stream into the o2 sensor.

HyundaiKitCoupe

Ok DTN, it worked. No CEL. There is one slight problem though.

I just installed my BBTB before I put these spacers in. The car impressively pulled and ripped the street. Now it almost runs like it did before the BBTB. It could be that I just got used to the power, but did you notice a noticeable decrease in power when you installed yours? Or is it just in my mind?

This leads me to my second issue. I'm questioning keeping the spacers on after emissions because I'm reading that using non-foulers leans out the mixture causing nitrogen oxide to build up and destroying the engine over time. You mentioned that the readings were the same as before though?

DTN

You only put a fouler on the rear o2 sensor. The front o2 sensor directly controls the air/fuel mixture. The 2nd o2 sensor is for monitoring efficiency of the catalytic converter. Basically, this is to fool the sensor into thinking that there is less of everything coming out of the catalytic converter, being that the sensor only monitors o2, it thinks there is much less o2 and the fuel is constant.

If you put one on the front o2 sensor, then it will richen the fuel mixture which would probly decrease performance, put a heavier load on the catalytic converter and ultimately destroy it, causing your car to smoke badly down the road or clog the cat and decrease performance again.

I did not notice any performance difference. My exhaust noise was lessend as the fouler protruded into the exhaust pipe about 1/2" more then the sensor alone. If I were using a stock pipe, it may cause a problem with extra pressure in the pipe, but I'm using a 2.25" pipe.

As long as the light is gone, it is doing it's thing.

HyundaiKitCoupe

^ahhhh ok. i have two. That totally clears it up then. i'll be working on my handbrake cable next week i'll take out the front one. that explains it, I'm such a dummy.

but it works great and i wouldn't have ever thought of it if you hadn't brought it up.

REDZMAN

Which fouler are you guy using?

I used the threads from here and NT.com before and none of the ones I've bought from the local auto stores work (these are in the "HELP" section of your auto store) yet.

I'm asking because there are several different sizes, and none have fit my o2 sensor yet.

DTN

Mine looked like this one
http://cgi.ebay.com/ebaymotors/TITANIUM-HY...emZ270288631837

But I can't see the tip. Mine has a covered opening with a 1/4" hole in the tip.

If this does not work for you, then fill the end with JB weld and then drill a small hole in the tip.

image hosted as e-bay link will only work for a few weeks after the auction closes

HyundaiKitCoupe

mine didn't have any tips, they were just straight through. the second one i ordered look a bit shorter than that but still the same.

one i have look like this:

i'll have the first one off thinking we needed two, in case you need it let me know. not sure if it's what you're looking for, or if it will work from what you have tried already.

REDZMAN

I'll take it, that way I can cross reference it with the ones I have and the ones at Checker Auto, so everyone knows exactly what part number to get, otherwise everyone will keep over spending and buying the ones on ebay instead of one down the street.

Tell me what you paid, I'll pay half.