fedann

I removed the lower right hand 10 amp fuse and the exhaust does not stay open. Why?

spdkilz911

That is the correct fuse. Silly question: Are you sure you have the NPP exhaust? It has happened before.

fedann

correct fuse...yes. NPP operates correctly when eccelerating and over 3500 RPMs. When the fuse is removed the acurators should open.........they don't I took it for a ride and it is quite as a mouse

haljensen

Is it a stock factory NPP in an '08 or newer?

Could be an aftermarket install with messed up wiring.

fedann

It is a stock 2010 Corvette with NPP exhaust. I've got to believe it's messed up wiring somewhere. I was just wondering if anybody else had encountered this

wilburn205

Just get a mild to wild kit and plug 10 amp slot. It's all good.

haljensen

Did you buy it new?

Is the NPP listed on the glove compartment label as a factory option?

fedann

Ahh, just bought it used and here is no NPP on the list. There are a lot of other 3 letters but not NPP

haljensen

Then it's probably someones slick idea of a controller. You'll have to trace vacuum lines and wiring to find how they installed the controlls for the NPP flaps.

Doesn't one Vendor make a controller that has the flaps closed at startup and at rest? Maybe find a hidden switch? Or you're missing a remote/

HOXXOH

One can close the flaps at startup, but it's unlikely that even a vacuum reservoir would be able to maintain a closed position for any length of time. Upon hard acceleration a drop in vacuum would open the valve if the only connection was a vacuum line with no other control.

Another point the OP can check, is to see if the flaps are open when the engine is off and then close when it's running.

Also check to see if there is anything plugged in the heated seat fuse location other than a fuse, since that's a common location to draw power for an aftermarket controller. Also the right rear cubby is where a M2W box is usually mounted.