Hello all!

I recently had a Corsa exhaust installed on my 2000. I also have a costume intermediate pipe installed also. I bought it used so there is a dent in one of the cats. Previous owner says he hit a rock. I was told this would not affect anything. Well here I am driving along and the check engine light comes on. I pulled the code and it came back as P0430 TWC low efficiency bank 2. Could this damaged cat have anything to do with it and can I continue to drive the car? Hopefully it won't hurt anything. Thank you!

 

Well,,,,, The substrate inside the cat is a very precise honeycomb. Whith that size DENT,, It sure must have damaged the internal honeycomb catalyst.

Get an inferred thermometer and compare the two cats after you take the car for a drive and the engine is at FULL OPERATING TEMP. Both should be really close in temp reading.

Check the temp at the inlet pipe of both cats, the cat its self and the outlet pipes.


You can also use a hand held scanner that is able to read real time sensor data and read the PRE & POST O2 sensor readings


If the CAT is working properly, the pre O2 sensor will be cycling from 100 millivolts to 800 millivolts (at idle). The Post Cat O2 sensor should be reading a steady state reading and NOT fluctuating like the main O2 sensor.

If the POST O2 Sensor is following the main O2 sensor,, the CAT IS NOT WORKING!

Hope that helps.

NOTE,,, They sell CATs that you can weld directly into that space to replace that bad one.

If the CAT is damaged and can NOT flow properly, you will lose power on that bank. If the substrate is damaged enough, it could crumble and get blown out of the exhaust outlet. When you measure the temp of the cat, it will be exactly the same on inlet and outlet if the cat is damaged and NOT functioning!!! A properly operating CAT will be 200 or so deg hotter on the outlet pipe than the exhaust inlet.

 

Bet it has a hole in it. One of my original cats had a dent in it like that and some of the material was busted out. It had a hole all the way down one side. I replaced it with a Magnaflow and still got the same code, just not as often. I bought a low mile used H pipe off a forum member, no problems since.

Have you ran those cats before? Or did you just install them?

 

I just installed them for the first time

 

Looks like you don't have much choice, either replace the cat or have the rear sensors tuned out. Have you tried to change the sensors side to side? May have a weak sensor. Think they used to have some deals that plug in to fool the computer. I couldn't find any when I was having the problem. I know the Magnaflow cat I installed didn't work on my car. I still had the random throwing code deal on mine until I used the factory H pipe.

 

Bill is spot on,

Guarantee that dent smashed the hell out of 1/4 of the honeycomb inside that cat.

The previous owner probably had the rear O2's tuned out and the problem never showed up.


ON ANOTHER NOTE:

Bank 2 is the passenger side. That dent is on the drivers side pipe (bank 1). You can always swap your 02 sensors side to side and see if it correlates.