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Strange Sound (almost like a wastegate dumping to atmos)

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#1
So randomly on my way to lunch today all the sudden my car started making a loud wooshing sound whenever i would touch the gas. It would go away as soo as you lift. It almost sounds like a wastegate dumping to atmosphere. is it possible I have a hose loose, or a diverter valve issue?
 


Hijinx

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#4
What have you done to the car lately? Do you know what your boost is looking like, i.e. is it creeping because of the cold weather?
 


OP
aballphoto
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Thread Starter #5
What have you done to the car lately? Do you know what your boost is looking like, i.e. is it creeping because of the cold weather?
Car is stock, no idea what boost is doing.

I only drive it to work. Mostly highway. Temperature change has been drastic and we just had a cold snap (as much of the US did)
 


OP
aballphoto
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Thread Starter #8
So I tightened everything I could reach (I'm going to need to get some tools, so many tight spaces!)

I got about a turn and a half on everything on the intake. I haven't been able to take it out and drive it yet.
 


DHM1

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#9
Can you record and post what it sounds like? Does it only happen at a certain throttle position? Certain RPM? Do you feel anything in the seat or just an audible noise?
 


OP
aballphoto
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Thread Starter #10
Can you record and post what it sounds like? Does it only happen at a certain throttle position? Certain RPM? Do you feel anything in the seat or just an audible noise?
Only when I'm on the throttle, let off and it stops instantly. All RPM, it's just a wooshing sound, and if I put the window down its very audible.

My sound symposer isn't working until I drive the car for 20 mins. Which is strange because my car is kept in my garage every night where its 50-60 degrees, so it's not the cold.

I'll try and get a recording.
 


Hijinx

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#11
There are two sides to the sealed SS box. Pressure enters one side and is circulated through that a small hole in a flapper. That causes the flapper to vibrate; on the other side of the flaper aka other side of the seal, you hear the vibration. If the sound symposer were leaking externally you'd likely experience a loss in power. If the flapper seal itself is broken as there are basically four sealed sections in the SS box you'd probably not hear it. So I doubt that it's your sound symposer itself, unless it's leaking externally on the pressurized side. In which case, again, you'd experience some power loss due to boost leak.
 


OP
aballphoto
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Thread Starter #12
There are two sides to the sealed SS box. Pressure enters one side and is circulated through that a small hole in a flapper. That causes the flapper to vibrate; on the other side of the flaper aka other side of the seal, you hear the vibration. If the sound symposer were leaking externally you'd likely experience a loss in power. If the flapper seal itself is broken as there are basically four sealed sections in the SS box you'd probably not hear it. So I doubt that it's your sound symposer itself, unless it's leaking externally on the pressurized side. In which case, again, you'd experience some power loss due to boost leak.
There might be a slight loss in power. I noticed today that it struggled to spin my snow tires in second. Hard to know for sure without an AP.
 


DHM1

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#13
Only when I'm on the throttle, let off and it stops instantly. All RPM, it's just a wooshing sound, and if I put the window down its very audible.

My sound symposer isn't working until I drive the car for 20 mins. Which is strange because my car is kept in my garage every night where its 50-60 degrees, so it's not the cold.

I'll try and get a recording.
If you floor it it still makes the noise? Is the noise like.... on off on off on off on off. Also you said you cant feel it? If it is the sound symposer please PM me. Also I don't know how your sound symposer would not work? Its just a mechanical device. Like stated already its a diaphragm that vibrates and should always work. I have seen some fiesta's surge since it has been getting cold. but it only happens when cruising and some acceleration. It goes away at WOT.

Russ
 


OP
aballphoto
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Thread Starter #14
If you floor it it still makes the noise? Is the noise like.... on off on off on off on off. Also you said you cant feel it? If it is the sound symposer please PM me. Also I don't know how your sound symposer would not work? Its just a mechanical device. Like stated already its a diaphragm that vibrates and should always work. I have seen some fiesta's surge since it has been getting cold. but it only happens when cruising and some acceleration. It goes away at WOT.

Russ
If I floor it and let it build boost it gets louder. AS stated it sounds like a wastegate dumping to atmosphere. Soon as I left of the gas, no noise. Soon as I touch the gas, noise. So it's not related to boost, but definitely intake.

The symposer does not work. I'm not really concerned with how it works, all I know is that it doesn't until the car is nice and warm.
 


Hijinx

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#15
The flapper aka diaphragm (lol) is allowed to move by way of flexible rubber. I don't think I'd be too far off to assume that when it's really cold, the rubber isn't quite ready to move yet. When you're troubleshooting things, it's important to know how/why the way they do so you're not just pulling/replacing parts all willy-nilly.

Anyway, it would be awesome if we could know what kind of boost you're seeing. A few more questions:

Have you checked all theses lines: i.e. wastegate, bypass valve, wastegate ref on the intake? Also, I know you've said you've checked your clamps, but it's cold so I'm guessing you've checked all but two; the ones on the intercooler. They are a pain if someone on the assy line was pissed off and orientated the clamps in a terrible way. Does this sound have a distinct pitch that rises and falls with RPM?
 


DHM1

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If I floor it and let it build boost it gets louder. AS stated it sounds like a wastegate dumping to atmosphere. Soon as I left of the gas, no noise. Soon as I touch the gas, noise. So it's not related to boost, but definitely intake.

The symposer does not work. I'm not really concerned with how it works, all I know is that it doesn't until the car is nice and warm.
The only time I have heard that is when the wastegate "flutters" / surges because of an electrical issue or calibration issue. This you can hear in the intake and is pretty loud. Our BOV are a electronic solenoid so no real vacuum line issue there. If you want to poke around I would check the wastagate lines like said before. Also if you don't want the dealer to check the car I would be down to ship you my old sound symposer to test with or you can take yours apart. But from the sounds I might go to the dealer and make some noise.

Im curious as to what this is and what it sounds like.

Russ
 


OP
aballphoto
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Thread Starter #17
The flapper aka diaphragm (lol) is allowed to move by way of flexible rubber. I don't think I'd be too far off to assume that when it's really cold, the rubber isn't quite ready to move yet. When you're troubleshooting things, it's important to know how/why the way they do so you're not just pulling/replacing parts all willy-nilly.

Anyway, it would be awesome if we could know what kind of boost you're seeing. A few more questions:

Have you checked all theses lines: i.e. wastegate, bypass valve, wastegate ref on the intake? Also, I know you've said you've checked your clamps, but it's cold so I'm guessing you've checked all but two; the ones on the intercooler. They are a pain if someone on the assy line was pissed off and orientated the clamps in a terrible way. Does this sound have a distinct pitch that rises and falls with RPM?
my car is stock, I do not have a cobb or anything. So, no boost readings. I have checked most of my clamps, but not all. I dont have a jack yet (just moved into my house). I'm familiar with how the car operates and its components. I'm not concerned with the engineering. I've spent the past 1 and a half decades racing BMW's and anything else someone let me sit down in, not unfamiliar with the troubleshooting process. Though, this is my first turbo car.

The only time I have heard that is when the wastegate "flutters" / surges because of an electrical issue or calibration issue. This you can hear in the intake and is pretty loud. Our BOV are a electronic solenoid so no real vacuum line issue there. If you want to poke around I would check the wastagate lines like said before. Also if you don't want the dealer to check the car I would be down to ship you my old sound symposer to test with or you can take yours apart. But from the sounds I might go to the dealer and make some noise.

Im curious as to what this is and what it sounds like.

Russ
Exactly, and thats the thing, it still does those flutters and I can hear the turbo just fine, but now there is this loud noise. I poked around the engine bay and under the car last night and didnt find anything.

I will be taking it to the dealer tomorrow.
 


DHM1

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#18
my car is stock, I do not have a cobb or anything. So, no boost readings. I have checked most of my clamps, but not all. I dont have a jack yet (just moved into my house). I'm familiar with how the car operates and its components. I'm not concerned with the engineering. I've spent the past 1 and a half decades racing BMW's and anything else someone let me sit down in, not unfamiliar with the troubleshooting process. Though, this is my first turbo car.



Exactly, and thats the thing, it still does those flutters and I can hear the turbo just fine, but now there is this loud noise. I poked around the engine bay and under the car last night and didnt find anything.

I will be taking it to the dealer tomorrow.
Please keep us updated

Thanks

Russ
 


OP
aballphoto
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Thread Starter #19
Please keep us updated

Thanks

Russ
Will do. I think it might be a minor boost leak. Once the car heats up (25+ mins of driving) it sort of goes away, at least to where I can differentiate between the noise and the injector tick.
 


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