C6Whatever

Today I was out driving in Sport mode (not using paddle shift) was getting on expressway. I had to get on it a little heavy to merge in to traffic. My pipes opened all the way. Once I was on the expressway in traffic I noticed pipes were still open. Never had it happen before. As I drove through town I noticed they weren't closing at all. As I stopped at red lights I would try putting it in park then in drive but it didn't change anything. After driving for a few blocks or more at a low rate of speed I noticed my pipes were closed and quiet again. Tonight my husband and I went out to eat so I told him about it. So of course he puts his foot in it and it happens again. He tried stopping, put in park, then in drive- still open..... After a little bit of slow driving pipes close and everything is quiet again.....
I have tried finding anything on this and haven't been able to.
Anyone able to help with this? Is it normal?

Lisa

Travelor

Do you get the same "stuck open" problem in the "normal" mode?

Richie Fazio

I'm pretty sure in competitive driving mode the flaps will open at 2800rpms under heavy load, but I believe they should still close once you resume to normal driving. Please correct me if I am wrong if that only applies to the zo6 and zr1.

Travelor

The reason I asked was to determine if there was a problem wit the Sport mode or the NPP system. If the flaps stick in both modes, I would suspect a problem with the NPP system, however there was no mention of them sticking just after start up.

????? so far................

C6Whatever

So far they have just stayed open in the sport mode. They have not done in when staring the car or the the D position......
Now what?

Lisa

CO Lightfoot

Definitely not normal. Never happened with my 09 Z51 NPP C6.

Just-a-Guess: You've got a build-up of carbon in the exhaust pipe that causes the NPP flaps to stick open temporarily.

With a flashlight, take a look in the two middle exhaust pipes. Not sure how you'd clean 'em... maybe someone will chime in.

Do you have an exhaust controller (Mild-to-Wild, Sunset, etc)? This would allow you to open & close the exhaust at idle while parked -- to confirm that your NPP flaps operate smoothly.

Or, you can do the same thing by removing the EXH MDL fuse in the passenger footwell. To find this fuse, see pg 5-97 in the 08 online owners manual: http://www.gmpartshouse.com/download...08corvette.pdf

Of course, inspect the fuse, make sure it's okay.

Also inspect the rest of the NPP exhaust system, especially the vacuum hoses.

Let us know what finally fixes it.

C6Whatever

Jeff
I don't have a Mild 2 Wild on my car. After it goes back to the quiet mode (lclosed pipes) I have tried it in the drive position and it opens and closes normal.....
I thought fuse could be bad but then I don't understand why it would work fine in D but in S it gets stuck open... Same thing with a vacuum line


Lisa