what the hell does that mean? i got a cel and this is what it turned out to be.

my car developed a wicked rattle somewhere in the exhaust system after my last track day.

it was at the shop the other day and we couldn't tell if it was the cats or the mufflers. unfortunately i got the cel after i left the shop so i couldn't pass that info along.

are my cats shot? i've never had a set of cats quit on a car before.

 

What is the exact code that's showing?

 

I already cleared it and neglected to write it down. It was something like P0420.... It threw the code at around 56mph under 15% throttle. I forget the RPM's. It was low as I was just cruising.

 

Wow, I have a better memory than I thought. That was the code.

Here's a link to the code explanation. I was hoping someone would know what it is generally indicative on our cars though.

http://www.obd-codes.com/p0420

 

A cat low eff. code can also be tripped due to an intermit lean condition. (dirty MAF/plugs) I'd say resistance test & replace the faulty O2 first then see if the light comes back on. There is a possiblility that your rattle is one of the convertors internally broken up.

 

I'm leaning towards the latter being that something in my exhaust system is rattling like crazy. I do get system bank one too lean CELs from time to time, but I run a wideband AF gauge and I'm generally on the rich side. Something wacky is going on there. Maybe the cats are completely degraded and throwing the system out of whack. I cleared the CEL and it hasn't come back on yet.

 

Maybe time for 100 cell cats or cat delete? :-)

 

If it's rattling I would suspect the cat/cats. I think they are covered under warrenty for 7-8 years free. The problem is not letting them look under your hood. If they will not cover then I have an extra used set for a 2000 laying around.

 

Do you have any other fault codes. If you have an aging sensor fault code then it could be a bad sensor not the cat. If there really are no codes then you may have a bad cat. Considering you have something rattling, then I would assume is your cat.

got this from the ODB manual:

P0420 TWC conversion, bank 1 - above limit
Possible causes:
- Oxygen sensor ahead of and after TWC exchanged
- Valve lift fault
- Aged oxygen sensor after TWC
- TWC faulty

Good luck

 

Deputy, were you still running stock cats? Supercharger + Stock Cats + Track Use can equal a blown-out cat. I would definately swap them out for some high-flow cats since you are flowing so much more air than normal. PM me for more details if you are curious.

 

Hmmm. I'll have to call the dealer and see what they say. Although I'm confident I'll probably just hear laughing on the other end of the phone since they know it's supercharged and they know it's been on the track

 

I do get system bank one too lean every so often. Usually when there are major ambient temp fluctuations. I'm not sure if they're all related. Could be...

 

I tried the cat delete once. It was obnoxious. Way too loud! Way louder than the car without mufflers.

How many cells do the stock cats have? I saw a set of performance cats on fleabay and they were 200 cell. I thought the factory was 200 cell?

 

If the engine is tuned properly, the SC has no more and no less effect on the CATS. If in fact your CATS get damaged, the damage would have been caused by the same thing, with or without FI.

I suggest you take a look at the after cat reading and compare them to each other. As I suggested years back, I have to assume you have recorded all the various engine parameters available through your scanner. Look for a change in one or more of them.

Often, a bad tank of gas can cause a false CEL related to the cats, especially when they get old. Cats should still be under full warranty.

When you say 1 bank gets a "too lean" code, what code?

 

I wish I could remember. Unfortunately I don't know how to record these errors with my scanner. It will display and clear them, but I haven't figured out how to save them, if you can at all...

I wish I had taken some readings and recorded them as you suggested. I didn't do that either. What I can do is take some readings and post them. Which readings should I be taking a look at?