CDinSing

Anyone had this happen? The exhaust flaps are stuck open. Not a bad thing, I like the more aggressive sound but I want to be sure it isn't a sign of a vacuum leak or other problem. Doesn't matter which position the button is in they are always full loud mode.

tstafford

As I recall in the old days there was a vacuum connector that could be unhooked to make this happen. (People did it intentionally for the noise). Maybe it fell off?

TimeWaitsFNM

When you figure it out, let me know so I can stop pushing the button every time

PhilT3 (PT3)

Simply disconnect the vacuum tubes going to the valve. Cap the vacuum line and zip tie out of the way.

Done. Valves opened permanently.

tonymission

My race shop put BB's in the line where they connect so they're always open. I much prefer it cruising around town at lower RPMs.

Mike in CA

Just to be clear, there are two valves; one for each exhaust pipe, They are located on either side of the center muffler. The vacuum line on each side can be plugged as shown in the pic below to keep the valves open. The vacuum line should also be secured so it doesn't flop around. (I think there were minor changes to the valve configuration after 2014 but the principle is the same). I did this mod but eventually returned the exhaust to stock as I felt there was a small loss of low end torque and the sound wasn't as pleasant as I'd hoped. Keep in mind that the ECU on the 991 GT3, unlike previous models, is designed to optimize performance with the exhaust valves functioning.

To the OP, I'd check your valve connections first to make sure something hasn't come loose. Also, you can reach behind each valve and operate the linkage manually to make sure the valves aren't sticking. If it's not either of those two things it may be an issue with a vacuum leak elsewhere or even with your ECU.

Steve1788

That happened to me once on a weekend drive, however it went back to normal after re-start. Loved it so much that I permanently disconnect the vaccume line the following day.