Hey guys, i'm back, its been a few months since ive been on but its emissions time and got a few questions.

Has anyone else done the catless cel fix where you crimp in a resistor in the black wire of the second o2 sensor?

Does it just throw the computer into a "loop" tricking it into thinking there is a cat there when there isn't

The reason why i'm asking is because i've put the the resistor in driven about 35 miles now with no cel (old code was warm up catalyst efficiency below threshold)(obviously)

Now, Missouri emissions testing basically just does a diagonostic on your car to make sure you are throwing no codes however just because the scanner reads "pass" doesn't mean it will. In Missouri (and i'm sure probably everywhere especially cali) they do a full scan making sure your 02 heater circuit is working, egr valve, catalytic converter, etc..

well when i do the MIL status testing on my car it still shows a couple of them like o2(something) and catalytic still shows "INC" or incomplete if it shows that when i go for emissions they will still fail it. so will that 'inc' ever go away after driving more or will it always say 'inc' because the resistor is throwing it in a loop?

 

For those who are wondering this fix does NOT work. After about 65 miles. The CEL does come back on with the same code. This fix make work on speed3's as discussed in the forum but does NOT work with regular 3's. I followed the instructions as indicated.

 

actually it does, the problem its a hit or miss ive been fortunate enough that i dont even need to do this little trick, i have an obx header

 

Yeah, i cut the black wire pretty close to the connector, and sodered (I know that spelling is wrong) it in, i disconnected the battery, hooked it back up, drove around a while and the light came back on. still the same code, (warm up catalyst efficiency below threshold) actually its throwing the code "twice" just one is "pending"

 

The black wire is ground i believe, gray power and the two whites are heater wires, shich header did you get?

 

I got the obx header like you do, i got it along with the down pipe combo where the down pipe is is pretty much a resonator that takes place of the the flex pipe. I've tried using fowler in the second sensor position but then i just get the code of "slow response" instead of "warm up below threshold"

This is where i got the fix...They say to use the black wire. Which I thought the same as you why would they use the ground. However, somehow i doubt they would have used different wiring schemes for o2 sensors for the regular 3 compared to the speed3.

http://www.mazda3forums.com/index.php?topic=120639.0

 

I would love to go header, Vibrant or Draxas being my choice, but this is exactly one reason I will probably never do it. It's just not worth the worry and aggrevation to me for my DD. Plus I would prefer the cat stay in the system. As far as I know, there is no header yet designed to allow that to happen.

 

well its a universal bosch 4 wire plug, the black wire is actually signal and the gray is ground. I have already seen that post a while back while i was looking for solutions just in case my cel came on for that reason, but after 5k+ miles w/o one *knocks on wood* i figured i was the lucky few that didnt need to do this trick. Like i said before its a 50/50 shot on if the cel comes on for that code, some are lucky some not so lucky, ive even heard that the vibrant header has actually caused a cel to come on, now if its from improper install or leaks i dont know, but with these cars its lucky chance something stupid/annoying doesnt happen when doing the small upgrades

 

Yeah, I still have my old header w/cat in the basement I'm going to have it reinstalled on wednesday, i'm pretty much done messing around with this car. as we all know its not the easiest to tune or at least with out money anyway. So i'll have an obx header laying around lol. This car is my dd and i can't keep going back and forth with it like i have.

I was contemplating the turbo set up for a while but again, the turbo mani gets rid of the cat like that header would and still wouldn't pass emissions not to mention i have an autotragic. I've already burned one tranny at 90k miles when my front diff. literally turned to dust. I can't imagine how fast it would go with with the turbo set up lol. I'm pretty sure cosworth makes a better front diff for our cars for around $2k lol even if you got that you'd probably burn the hell out of the tq converter.

i'm stickin with easy bolt on's for the rest of the way, granted i won't see huge power gains but if i get a decent tune on it. shouldn't be all that bad.

 

So the two of you basically have the same car... 2.0L, auto w/OBX? Interesting.
Yeah it is kinda' disappointing that the ECU is not more "trainable" in these, but I think that's getting to be more the norm than the exception.

You say you tried the anti-fouler trick and that didn't work either?