I'm wondering if there is a way to tell if a catalytic converter needs to be replaced. I bought an N-tech HF cat about two years ago. Things were great. I passed the emissions test with no issues running the M2 ECU and all the bolt-ons & stock motor.

Now, I have a streetported motor, 1300cc secondaries, PFC, WB, and the same bolt-on parts. I have my AFR's tuned to 13.4-6 at idle 14.5 at cruise and 10.8-11.4 at WOT.

The probelm is that my car smells pretty bad. Is my cat no longer working? How can I tell if it needs replacing. How often do you need to replace these things?

 

from what i understand when they start producing a very strong odor very similar to rotten eggs, hope this helps.

 

Get a Pressure gauge, plug it into the O2 sensor bung, and read how much backpressure you have 6+ Psi, and it's clogged, rotten egg smell and it's bad... but most get clogged before they go bad...

 

yea that rotton egg smell, and if its glowing thats bad too

 

when in doubt, just get a mp or punch out your car (its really not htat hard, just grab a long pipe...)

 

/\ dont ghetto the car. also with a mid you will need to be thinking about controlling boost creep. what is you vac reading? from boost when you let off does it slowly go to max vac. it should swing pos to neg very quickly.

 

a sound like big rocks being tossed around in a metal bucket is a good (bad) sign. this means the cat is FUBAR'd

 

hollowing out a cat is not ghetoing, in somestates if a cop sees the midpipe your screwed. at least with the hollow cat its not as obvious

 

I couldn't achieve boost over about 4 psi with a bad cat.

 

jpandes,

if your cat is fubar and you still need to pass emissions why not wait for rotaryextreme and rynberg to finish testing on the new cat technology....

https://www.rx7club.com/forum/showth...nightsport+cat

 

Thanks for all of the comments and input guys.

Hmmm, I 'm not sure if it smells like rotten eggs. But it stinks.

After speaking with Hyperion tonight, we're guessing that the new PFC might be to blame for the exhaust smelling bad. I'm gonna try turning off the 02 sensor f/b setting off and/or unplugging the airpump to see if that changes things.

I also don't think the cat is clogged. My car spools up nicely and feels pretty strong.

BTW, I have a brand new SS MP sitting in the garage I'm just not too crazy about making my car any louder than it already is. It's my daily driver.

I'll report back on my findings...

 

Well, I unplugged the airpump and the car still smells buut is a different smell. So I guess I was getting the rotten egg smell before. I didn;t recognize it because I have never smelled rotten eggs before

Now I just need to change the O2 closed loop setting to off.