Ok I have an 04 3i with headers and its starting to become a B!tch for real. Our cars have two cat converters Stock. One on the header which has been eliminated with the new header I have on. So basically the set up i have now is that there is two inline oxygen sensors with out a cat converter inbetween. Typically there are many fixes for this. However, none seem to work and I need some ideas. I have tired the O2 sensors holder or "bung" as VooDoo performance likes to call it. It's a good idea. However, I throw the code that says. "O2 sensor bank 2 slow response" I have also tried the MIL eliminator wires I throw another, different, code "O2 sensor bank 2 No activity". I've tried having nothing at all, just two straight O2 sensors and I get "O2 sensor bank 2 warm up cat below threshold" How else can I fix this???? the only idea I had in mind was I plug the hole where the second oxygen sensor is at cut that sensors wires in half and extend the wiring and making a NEW hole after the cars main cat right after the flex pipe. However I don't know if that will work because I don't know if that cat converter posses the same tendencies as the warm up cat does and if it will read right... I don't have that resonator right afterwards so i have plenty of piping to work with....I have to find some kind of fix for this otherwise i'll never pass emissions. My last resort is going to an exhaust shop and having to order the stock header again for I think they said $550 plus install

 

sorry, im not going to be any help here. i just have one question. i was going to suggest to just reinstall the stock header when you go in for emissions testing, but then i saw you have to re-order them. did you sell your old stock header or can they not be used anymore after uninstall? whats the deal?

 

Well what I did was, at the time I worked at Auto Zone which then right behind me was a Car-x. Typically, they won't install headers but since I knew the people that worked there because I delt with them, pretty much, on a daily basis they went ahead and installed them any way. The guy that did it owned like a 98 Civic that was all moded out and had headers on it, so he was at least familar with them. So basically I dropped my car off went next door to work and he brought the car over with the O2 sensor holder in it and for like two days it never came on, then after it came on and I erased it, it started coming on more frequently, always the same code, every 20-30miles or so. This happens with every 'fix' I've tired. Well anyway, when he brough it back over I didn't think to ask him what he did with my original header. I'm assuming he threw it away. I'm going up there tomorrow to see if they still have it. I don't know why they would keep it though. This was also done sometime in March so I REALLY don't think they still have it.

No the stock header CAN'T be used again with out modification. All the headers i've seen for our cars always stop short. (Obx and Vibrant) A few feet short actually lol. Our headers are a one piece design from the block to the first O2 sensor, to the warm up cat, to the second O2 sensor, to the flex pipe and BAM flange to the main cat. All of the aftermarket manufactures seem to think its a two piece design and cut the header short right between the second O2 sensor and the flex pipe. So basically what you'd have to do is take the stock one piece design and cut it in half make a flange that you made to fit the Aftermarket header and that would work. The only thing is I don't know how big the warm up cat is compared to the aftermarket header so if its longer you might be pushing back the exhaust a little bit and your tail pipe will stick out a bit further. But who cares if you only doing it for emissions lol.

 

Trust me, these mazdas are a b!tch to tune and I'm finding out the freakin hard way lol