Exhaust Flutter at start up

[5.Oh Crush]

Has anyone had this? The exhaust sounds bad until I turn on active exhaust or turn car off and restart. Is the flap sticking? Thanks.

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[Sammy]

Has anyone had this? The exhaust sounds bad until I turn on active exhaust or turn car off and restart. Is the flap sticking? Thanks.

The same thing happened to mine. Fire it up and in a span of 2 seconds it goes from very loud-----more muted-------very loud. Kind of strange. It is like the system is testing the flaps on startup. Then it settles down. I only noticed it on cold starts.

 

[montreal ponies]

Normal caracteristic of the exhaust valves, they all do it.

 

[Bender]

If the car is turned off with the mufflers in sport mode, it just the computer re calibrating the valve servos since it designed to be in normal mode upon start up. If you place the car back into normal exhaust mode it should go away or only flutter once

 

[Ronp]

When you first get in the car, press in the clutch for a couple seconds before starting and it wont do that. You'll actually here the exhaust valves opening and closing. I cant stand when i forget and it does what you are talkjng about.

 

[5.Oh Crush]

When you first get in the car, press in the clutch for a couple seconds before starting and it wont do that. You'll actually here the exhaust valves opening and closing. I cant stand when i forget and it does what you are talkjng about.

Thanks. I had the problem over the weekend again even after warm start. I will hold clutch longer next time.

:cheers:

 

[crazymayhem]

When you first get in the car, press in the clutch for a couple seconds before starting and it wont do that. You'll actually here the exhaust valves opening and closing. I cant stand when i forget and it does what you are talkjng about.

Wasnt there a trick like that - or is that it - to start in sport exahust mode?

 

[nastang87xx]

When you first get in the car, press in the clutch for a couple seconds before starting and it wont do that. You'll actually here the exhaust valves opening and closing. I cant stand when i forget and it does what you are talkjng about.

So THAT's what that humming noise is...guess that shows you how often I drive in normal mode.

 

[5.Oh Crush]

I thought it always started in sport mode on initial "growl" and defaulted off. Then you have to turn it onto sport mode. Of course, I can put it in reverse and it does not do the initial sport mode growl.

 

[nastang87xx]

I thought it always started in sport mode on initial "growl" and defaulted off. Then you have to turn it onto sport mode. Of course, I can put it in reverse and it does not do the initial sport mode growl.

I always thought the car did a valve check on startup depending on a certain number of conditions. I never could figure out what they are but the clutch thing does make sense.

 

[J_Maher_AMG]

So THAT's what that humming noise is...guess that shows you how often I drive in normal mode.

The humming noise you here when you first put in the clutch is actually the fuel pump priming, you'll hear an audible almost clicking noise of the exhaust valves opening/closing.

I agree though, normal mode may as well be called non-existent for me

 

[crazymayhem]

Im pretty sure I read it somewhere in a post in a thread last year, but cant find it via the search function, but didnt somebody post a trick where holding down the clutch for a few seconds before actually starting cycles to valves open mode? Or did I misread that somewhere?

 

[nastang87xx]

The humming noise you here when you first put in the clutch is actually the fuel pump priming, you'll hear an audible almost clicking noise of the exhaust valves opening/closing.

I agree though, normal mode may as well be called non-existent for me

Okay, that makes more sense. I thought it was something with the injectors/pump initially before so was definitely thrown off. The click'ish noise I really had to listen for.

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