I had earlier post regarding P0420 code in my 08 Tl Type S. Today called the local muffler shop and apparently they guy have the same car I have and asked him if they could do the Spark Plug Defouler thing with the 02 Sensor to get rid of the CEL but he said this won't help because the code is specifically for the CAT Bank 1. My questions are:

What are my options beside putting in a new or used CAT which I know will be very expensive close to 1K or more?
They guy suggested getting a RV6 Pre CAT delete and go with a straight pipe and leave the rest of the exhaust to stock so it wont be loud but since I don't have resonator it will be hella loud I guess. The part cost something around 370 USD and the shop would charge me 400 CAD to put it in and then I will have to flash a custom software I believe which will be the same as putting in a brand new CAT?
Is there a third option or any easy fix or I am stuck?
What if i just keep driving the car would it damage anything or reduce performance overtime? Apparently right now car runs very fine with no hesitation or smell or RPM going up and down at idle? The car only has 155000 kms on it, tried CataClean but did not help.

Any help or suggestion is highly appreciated.

 

P0420 shouldn't affect performance, unless cat is falling apart and will block exhaust flow. Defoulers sometimes work, but not many shops will want to touch this as technically it's not legal (let me know if I'm wrong).

Precats delete will completely get rid of catalytic converters and will not help with P0420. They will cause this code. I didn't hear about flashing the custom software to get rid of P0420.
From my experience some people go with catless systems on the car, and live with check engine light, and when time comes to do the inspection they put stock exhaust back on to pass it.

If P0420 happens to my car, I will try defouler first.

 

I would replace my O2 before I did much else. It is the cheapest of the options I think. Or at least get a ODBII reader on there to watch the O2 sensor behaviors from cold to warm to hot. See if it is obvious the O2 sensor is not responding or if it is just out of range.

 

How are you coming to a sum of $1000 for a used even “new” catalytic converter

 

The guy said if you don't change things in the computer as well the code will come back on since its an aftermarket part and the computer may think it still not working properly so the code will stay on.

 

I asked a mechanic and that's what he told. Could you help me finding one and what's usually the price to change them? Any idea?

 

The guy i talked to said the car is smart enough to tell if it is the 02 sensor or not if it is p0420 it is definitely the CAT.

 

The guy is wrong.

All the information the ECU has about the condition of the catalyst comes from the O2 sensor(s) and lots of assumptions (including the assumption that the coolant temp sensor reading is right and the exhaust is contained within the system - no leaks among other things). if the signal from the sensor is wrong so is the ECU's determination of the condition of the catalyst.

you have to be suspicious when a shop says "oh it's definitely the most expensive part... your car would know if it wasn't"

 

Well, if the sensor is out of range a code would be seen indicating O2 sensor problem, heater circuit malfunction,
circuit malfunction, low voltage, high voltage, but a 420 is most likely the converter. Having said that, an O2 sensor
can be checked, or if easily accessible, exchange the 2 sensors and watch for the code, same side or moved with
the sensor. Personally, if it is the converter, but not restricted, I'd just go with the two spark plug non-foulers as I've
found that the inexpensive aftermarket converters usually don't live a long life unless you spend $$$ and get one with
an extended, or even lifetime warranty.

 

I am going to check the voltage of the 02 sensors with code reader see if it is the sensor or not. by the way the spark plug defouler thing is just to get rid of the engine light right because let say if it is the CAT then the defouler would just prevent the light from coming up even tho the problem exist am i right?

 

The 420 is a code that as we know, most likely the cat is not doing it's job. With the 2 non-foulers,
the cat will naturally act and perform the same, but no cel. Now depending on the emissions test
in your area, one wouldn't know if it would pass unless tested. Here in Jersey they just scan the
OBDII to make certain no fault codes, no codes it passes.

 

Hey bud the 2 non-fouler you mean both the 02 sensor right because there is 1 on the very front and the one in the back near to the CAT? and the car is running with active status and i just want to get rid of the CEL so i think i should be ok? Also what could've caused the CAT to fail any idea?

 

You put non-foulers only on second (oxygen) sensors that are behind the catalitic converters. Put one only on the bank that causes the code to pop up. Leave AF ratio sensors alone or car will not run right.

 

As the O2 sensor is longer than the non-fouler, you'll need 2 non-foulers for one O2 sensor.
Drill out the end on one non-fouler, then insert that one into the other non fouler.
You'll also need the correct threads on the non fouler.
Thought I'd look up a video to give you an idea, so this is the first one found:

 

Buy rv6 pre cat deletes. They come with the defoulers. And they really wake the car up. Youll get some more pep. Youll love them. Best bang for its buck!! No check engine lights if defoulers are installed correctly.