View Full Version : Catalytic converter issues

08-04-2012, 10:36 PM
So heres the deal, I've had to replace my cat twice already and I just got the bird up and running and already the check engine light is on again saying the catalyst system is performing below stanadard. Any idea why the cat keep on messing up? Has anyone else had this problem? I'll probably just do the defouler mod or an emulator but I just don't know whats up.

08-05-2012, 08:36 AM
Have you narrowed it down to the cat, the reason why I ask is it could be just the sensor. Just because the.code says it does not mean its the actual part

08-05-2012, 08:48 AM
well not exactly... I would think the shops I've taken her to would have checked that. Is there any way I could check it? or is it a "replace and see" kind of thing?

08-05-2012, 08:58 AM
Sounds like the O2 sensor after the cat. Mine did the same thing.

08-05-2012, 09:14 AM
Well the shops should have checked everything, do you know them good?? If it's just a shop that you stopped by, some techs will try to get the most money out of you

08-05-2012, 11:33 AM
Id tune it out. Only problem would be your state envision regulations. Here they don't check for anything. My cat is gone.

08-05-2012, 01:51 PM
I have my cat, but it's tuned out.

08-05-2012, 04:29 PM
Are you running really rich, or replacing the cat with high-flow cats?

The high-flow could throw a code just because they aren't as good quality and the car just assumes something is wrong.

08-05-2012, 10:46 PM
No the cat is standard. The first shop I went to I didnt know and had them fix it, when it "went out" again a while later I went back and they had closed... But the second shop I went to I new pretty well. A friend of the family worked there, they also replaced my engine when I acidently cracked the block. I'm going to call them and see what they think. When ever I replace it the code goes away for about a year or two and then comes back, so Idk. I need to invest in a wideband so I can make sure I'm not running too rich. I have a new exhaust to install but right now I'm just trying to get it to pass inspection so I can get my daily into the shop and still have a means of transportation.

08-06-2012, 08:44 AM
what gas are you running? I ran 93 (no tune) and my cats didn't last more than a year or 2

08-06-2012, 06:50 PM
I'm just running regular gas.

08-08-2012, 09:48 PM
im having the same problem i keep getting the 0420 code popping up and it has had the cat i currently have one it for 2 years so im trying to figure this one out.if it is the cat im just going to rig it up to where i done have to weld one on i could just bolt it on and off and use the magna flow warranty on it.bythe way i am running the magna flow high flow cat.

08-09-2012, 06:35 AM
I don't know if the F-Body world is the same, but in the W-Body world, if you replace your stock cat with a high-flow cat, 95% of the time the P0420 code WILL appear because the car THINKS the cat isn't performing correctly since the stock cat is so much more restrictive in flow.

Basically when we switch out our stock cat, we need to either put in a de-fouler for the rear o2 sensor, or tune the p0420 code out.

08-09-2012, 08:43 AM
tune FTW!

08-09-2012, 08:23 PM
Planning on tuning it out eventually, but for now I just ordered a ZZP Emulator.