kcheves

I beleive that's true for 997.1 cars. From 2009 onward, a separate PSE button is provided even if you have Sports Chrono.

ElVerde07

Makes sense. I definitely have PSE but no PSE button after further research. My car is 997.1

jhbrennan

Sure you don't have a button on the same row as the spoiler button, etc. that shows what looks like two exhaust tips? That's the PSE button.

ElVerde07

Yup, positive. I'd post up a photo if I was "with car" today at work. I've seen the photo online (looks like a shotgun or binoculars actually) and I definitely don't have the button. But I definitely have the PSE.

Little Green

Could have been the previous owner installed gundo/fisters on the car. Similar to PSE but it's on all the time.

ElVerde07

Definitely has the PSE... The exhaust is markedly louder when sport us engaged. Also the tailpipes match what PSE looks like.

BrakingBad

Any chance you could record a video of the event with your phone and upload it to youtube? It might be helpful in figuring out what is going on.

ElVerde07

Yeah, that's the next logical step isn't it? I'll be detailing it tonight so that will give me an opportunity to do so.

With my luck, it will probably refuse to make the sound tonight

kcheves

The theory on the table is that the PSE valves are clunking on shutdown. This would not be the case for a Gundo'd exhast.

Petza914

It's the PSE.

The reason it happened when you were playing wih the stereo in the car wihout the engine running is that the signal to the vacuum actuator switch in the engine compartment that sucks the valves closed via the vacuum lines probably energizes with the key in the accessory position, even without starting the engine. After shutdown, eventually the system loses enough vacuum where the springs in the exhaust valves pull them back open again. I have a Fabspeed Valvetronic Muffler and when mine release they sound more like a squeeky door and don't bang, but if the springs in the OEM PSE are stronger, I could see how it could make a bang sound. Here's a photo of my fabspeed setup where you can see the valves (they have the braided stainless vacuum lines running to them) - the factory PSE ones should look similar and be in a similar location.

ElVerde07

Wow that is an extremely helpful answer. After playing with it last night I was almost positive it was the stereo and some sort of electrical gremlin. It's certainly loud enough to sort of make you jump when the noise hits unexpectedly. It happens every time the key is removed.

Any thoughts on whether this is an issue that needs to be addressed by the dealership? Or if this is a "just live with it" situation?

Petza914

You can double-check to see if we're right. Just go back to the exhaust after removing the key and locate those valves. You should be able to see an arm on them move when the vacuum releases and that's when you'll hear the pop.

ElVerde07

We're talking about physically looking into the exhaust pipes with a flashlight here? I can do that.

Petza914

No, we're not looking in the exhaust pipe. You need to find the little rod (see red box) that is part of the valve assembly on the muffler. There's one on each side for each PSE muffler. The valve assembly should have a rubber vacuum line going to it. That rod will move one way when vacuum is established and the opposite way when vacuum is released and when it's released the spring inside is what moves it back and what I think is causing the noise you hear as the valve hits it's stop inside the assembly.

ElVerde07

I'm hoping I can do that without removing the bumper...I'll check it out.

I am ALMOST completely positive the noise is the stereo though. It is much louder inside the car than outside the car.