car flutters when I let off gas

[cadilacmike]

Alright I know another car fluttering sound, I've checked couldn't find the exact problem I'm having.

It doesn't matter how fast you going could be cruising 5-25 or WOT when you let off the gas it has flutter sound. Sounds like its close to BOV/intake area, but I know its not the BOV, under high boost it will flutter and I'll hear BOV right after. It's just any time the gas is released you can hear it flutter. It does seem the faster the louder though.

Part of my exhaust is banged up and rusty, could and exhaust leak cause this sound.

 

[simplejoe]

I'm not understanding "fluttering sound" gonna sound stupid, but did you check for play in your turbo? Anyone else with any other thoughts chime in.

 

[JosephMiranda]

Does it sound like this? [ame=http://m.youtube.com/watch?v=tvsD0JumeL8]Compressor surge HELP!!!!!! - YouTube[/ame]
If thats the case it may be your bov.

On a side note i know this ruined his turbo so be careful!

 

[WES_393]

The entire purpose of a BOV is to stop the turbo from fluttering when the throttle closes. So if the turbo flutters, it's an issue with the BOV. If it vents right after the surge then it's just too slow to react. Is it a real Greddy, or a knockoff? I'd suspect a vacuum leak or sticky valve.

Start by checking the vacuum line for leaks. It should also be decently sized, hooked to a large port on the manifold, and have no other lines T'd into it. If the line is good, then pop the top portion of the valve off and look for any tears or holes in the rubber diaphragm. If so, replace it with an NGR diaphragm. And remember to be careful not to pinch the diaphragm under the cap when re-assembling.

If those things check out, then pull the BOV off and try pushing the valve open by hand. It will take some finger muscle and probably stop after only an inch. But it shouldn't stick or feel notchy at any point. Make sure the O-ring on the valve isn't sticking to the seat. If so, it may need to be replaced or lightly greased. Also try opening the valve by pushing from different angles, like using both thumbs on one corner of the valve face.

I guarantee one of those steps will point out your problem.

 

[cadilacmike]

Does it sound like this? Compressor surge HELP!!!!!! - YouTube
If thats the case it may be your bov.

On a side note i know this ruined his turbo so be careful!

It kind of sounds like this, I noticed the BOV doesn't make it's sound until real high boost. My boost is set at 10psi right now and it ain't until 8-10 it makes its noise.

to WES_393: It does go to my manifold but it is also connected to a T. I'll post a video of the sound shortly.

OK, vacuum from BOV, goes to a T, one part of the T goes to intake manifold, other goes to boost controller to wastegate actuator.
Vacuum lines are good also, and it has a greddy stamp on it, I'm assuming it's legit.

[ame=http://youtu.be/zSciZtZmUks]HKS SSQV bov flutter aka surge - YouTube[/ame]

Sounds exactly like this except this guy has diff, BOV

 

[cadilacmike]

Well I played around with my BOV and adjusted it, seems to have been the problem after all. I still get the flutter sound but anything over 7-8 psi I barely hear it and hear all BOV now.