Ok,

100% stock C6, then I get an aftermarket exhaust. I won't say which one, because I love it and don't want to hurt the company, then on my way to pick up my full K&N kit at UPS I get an engine code. Turns out to be an O2 sensor, dealer clears it as a test and it comes back, they change the sensor, then I get P0430 which is "low catalyst efficiency bank 2", clear that as a test and it comes back, so far I have cleared it I think 5 times, never P0420 (bank 1). Guy at the dealership said it's probably just because it's higher flowing exhaust, but I had a hard time believing that. Called the company and they said they have only heard of people getting engine codes only about 2 other times out of all the Corvette kits sold. So, I began to wonder if maybe people are getting the codes and just accept it or if I really do have a real problem.

So, Has any body else gotten an engine code from JUST changing their mufflers? Or do I just have a bad converter?

Thanks,
Steven

Edit: Aftermarket Mufflers Only. Factory exhaust manifolds, factory cats, factory H-pipe.

Edit 2: For got to mention, I got the new mufflers a pretty good while ago and what initially confused me about it is that the light for the o2 sensor would come on for a few days then cut itself off, then finally it just stayed on before I got it replaced. But when the P0430 comes on it stays on.

By the way, the service manager is a very nice guy and he and his dad are both corvette guys and both on this forum. I told him I was going to make this post and plan on showing him this in a PM after a few days.

 

You have an exhaust leak...

 

Turn your o2 codes off. They are useless.

 

I tend to agree. Did you replace the gaskets during the install?

 

do you have stock cats? these codes means your cat is no good.

 

Did you go cats/headers or just axle back (after the H-pipe)?

 

Factory manifolds, factory cats, factory H-pipe.

 

I"ve never had it happen, and logic tells me that something else is going on. I wouldn't think any codes could be pulled by something going on after downstream of the cats. Like maybe during the install, when the H (or X) pipe was pulled off to install the pipes, they snagged something else by accident.

 

I doubt just a muffler change would cause the problem. The stock mufflers have a high flow rate already. With all the different brands out there and never hearing about this,it has to be a problem with YOUR car. How about re-installing the stock mufflers and see what happens?

 

I got the new mufflers a pretty good while ago and what initially confused me about it is that the light for the o2 sensor would come on for a few days then cut itself off, then finally it just stayed on before I got it replaced. But when the P0430 comes on it stays on.

 

I think you may have a bad cat in bank2. How bout put the stock muffler back on and let the dealer take care of the code for good.

 

I think the service manager at the dealer is starting to believe that it may be a converter problem too now.

 

ttt

 

I did headers on my C5 and it did burn out an 02 sensor.

 

yes, others have gotten the same code and have either elected to live with it or had their 'tuner' delete the code, and then there are others that have not received the code after installing long tube headers, high-flow cats, and exhaust.

it depends upon where the 'cats' are located after the install and or the approximate distance between the two o2 sensors.

a burnt o2 wire and or a contaminated sensor will also throw the code.

 

I would just go down the flow chart in the service manual for that code, it will have you do some wiring and connection checks. Also monitoring the 02 activity on a Tech2 scanner.

You could swap the 02s from side to side and see if the problem stays on that bank. Double check there are no leaks. 02s are pretty sensitive, all the knocking around from an exaust install can damage them pretty easy. Then maybe just a snafu that the second one is now also bad, or now the connection is loose.

If the service manual flow chart leads to replacing the cat, then that's what I'd do next. If that doesn't fix it, last thing left is some quirk in the new muffler isn't allowing the cat to work right. That has happened before, but pretty rare.

I'd also do a nice long wide open highway blast. Sometimes cats and
02's get a little sooted up and just need a red hot blast down the highway to clean them out.

 

Something was bumped or bothered. (wire on a 02 sensor possibly)
I had changed cat backs on my 98 & 05 with no problems. (along with thousands of other people)