"Bike Sproket" noise while letting off the trottle

[Joshua Frye]

Hey guys, I am new to this forum and the "audi world" but not new to car forums in general.. I will start and introduce myself, well I am Josh from the beautiful state of Vermont, I am a sophomore in college majoring in mechanical engineering, but have been working for 2 years as a mechanical engineer full time during summers part time during the school year...

I just purchased my 2005.5 Audi a4 6 speed manual a couple months ago with 120k from a dealer who just replaced the water pump, timing belt, and cam follower. I have just started hearing a noise when letting off the throttle, it sounds like a bike sprocket and sounds like its coming from my turbo. I read on here that it may be my DV, so I replaced the stock one with the piston type hoping it would resolve the problem which it didn't. The noise is not gear train related as it happens when I am stopped with my clutch fully engaged or with my car in between gears. The only time it seems to happen is when i let off the gas, and if i just barley tap the gas it goes away instantly but seems to start making the noise maybe a second after letting off.. happens while the car is cold, and while its warm... No codes whatsoever... I installed the ECS boost gauge and it seems to be boosting properly (12ish lbs) no fluttering.. I am new to the whole turbo game... buut hopefully this is enough info and someone can help me out!
Thanks!
-Joshua

[Nebone]

Hello fellow ME. The noise you are hearing is the HPFP slowing down. At least it is what I came to realizing in the last 3+ years of owning my B7.

[FraggyA4]

Hey guys, I am new to this forum and the "audi world" but not new to car forums in general.. I will start and introduce myself, well I am Josh from the beautiful state of Vermont, I am a sophomore in college majoring in mechanical engineering, but have been working for 2 years as a mechanical engineer full time during summers part time during the school year...

I just purchased my 2005.5 Audi a4 6 speed manual a couple months ago with 120k from a dealer who just replaced the water pump, timing belt, and cam follower. I have just started hearing a noise when letting off the throttle, it sounds like a bike sprocket and sounds like its coming from my turbo. I read on here that it may be my DV, so I replaced the stock one with the piston type hoping it would resolve the problem which it didn't. The noise is not gear train related as it happens when I am stopped with my clutch fully engaged or with my car in between gears. The only time it seems to happen is when i let off the gas, and if i just barley tap the gas it goes away instantly but seems to start making the noise maybe a second after letting off.. happens while the car is cold, and while its warm... No codes whatsoever... I installed the ECS boost gauge and it seems to be boosting properly (12ish lbs) no fluttering.. I am new to the whole turbo game... buut hopefully this is enough info and someone can help me out!
Thanks!
-Joshua

Does it sound like this:

https://www.youtube.com/watch?v=2P6JJd9XQ3A

[Joshua Frye]

No it does not sound like a flutter, its 100% stock.. and just did the DV

[Joshua Frye]

Hello fellow ME. The noise you are hearing is the HPFP slowing down. At least it is what I came to realizing in the last 3+ years of owning my B7.

Howdy! Okay what is a HPFP? my buddy has the same exact car and does not have the noise at all. Is this a huge problem, should I be worried? How do I go about fixing it? Really appreciate it man!

[jimrobbington]

I have a friend Josh Frey, pronounced the same. Lol. What you are describing does not sound turbo related. Nor does it sounds like the typical injector tapping diesely kinda sound. Sounds more like maybe the cam chain tensioner perhaps.

[jimrobbington]

Does it sounds like this?

2.0T FSI knocking sound, maybe cam chain tensione…: http://youtu.be/y-E7XKUAIgs

[Joshua Frye]

Does it sounds like this?

2.0T FSI knocking sound, maybe cam chain tensione…: http://youtu.be/y-E7XKUAIgs

Thanks for the reply but that is not what it sounds like, I would describe the sound as a bike sprocket (clicking) as its coasting down a hill. It only happens while letting off the throttle, it doesn't seem to have any power loss and no codes. I will try to record a video at a later time, but am currently at college with no camera.

[ZORT931]

I have the same noise. Mine also happens whenever I let off the throttle and am coasting while in gear. If I push the clutch in, the noise disappears. If I am in neutral, the sound is nonexistent. I can't figure out where the noise is coming from but my guess is transmission related.

[allstock]

I have the same noise. Mine also happens whenever I let off the throttle and am coasting while in gear. If I push the clutch in, the noise disappears. If I am in neutral, the sound is nonexistent. I can't figure out where the noise is coming from but my guess is transmission related.

Wastegate actuator rattle.

[jimrobbington]

Wastegate actuator rattle.
Boom, only answer left. Didn't someone recently post a thread about this and maybe fixing it?

[JDillon15]

Boom, only answer left. Didn't someone recently post a thread about this and maybe fixing it?

From what i know, there is not a fix. You have to replace the turbo. The clip you're refering to is for the b8. I could be wrong but that's what I found out when I looked into it.


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[Joshua Frye]

God damn.. replace the whole turbo?!?! if it is the wastegate couldn't I just replace that?? Also is this doing harm to my turbo?

[Joshua Frye]

Okay after watching some good ol' youtube videos I am 95% sure its the wastegate actuator rattle, some of the youtube videos stated that replacing the turbo was the rout.. well, honestly I still owe on the car, and cant really afford a new turbo at the moment.. I am wondering if running it the way it is, with the rattle is doing any long term damage?? also I saw a 2.0T vw video and the guy said he added this clip http://www.ecstuning.com/ES2210978/ and the noise stopped, another said he had to replace the wastegate?! I am wondering if anyone has ever used that clip, also same question as before, any long term risks and damages with this clip? how about replacing the wastegate, will that fix it? what is the correct way to fix this problem....the noise drives me nuts... but I cannot afford a new turbo at the moment especially if there is an easy fix such as this clip. looking forward to the responses, and a huge thanks to everyone who has commented and has ideas!

[FraggyA4]

Found the same problem in the B5 section
http://www.audizine.com/forum/showthread.php/429046-Has-Anyone-Rebuilt-their-K03-wastegate

[FraggyA4]

Sounds like it's just an annoyance. I wouldn't really worry about it causing failure. I'm guessing the metal piece just absorbs some of the vibration so you don't hear it. I would replace the turbo until you want to upgrade or it blows up.

[JDillon15]

Okay after watching some good ol' youtube videos I am 95% sure its the wastegate actuator rattle, some of the youtube videos stated that replacing the turbo was the rout.. well, honestly I still owe on the car, and cant really afford a new turbo at the moment.. I am wondering if running it the way it is, with the rattle is doing any long term damage?? also I saw a 2.0T vw video and the guy said he added this clip http://www.ecstuning.com/ES2210978/ and the noise stopped, another said he had to replace the wastegate?! I am wondering if anyone has ever used that clip, also same question as before, any long term risks and damages with this clip? how about replacing the wastegate, will that fix it? what is the correct way to fix this problem....the noise drives me nuts... but I cannot afford a new turbo at the moment especially if there is an easy fix such as this clip. looking forward to the responses, and a huge thanks to everyone who has commented and has ideas!

I can not believe that piece of metal is $40.. If you try it and it works, let us know. I might take the plunge.

If you feel mechanically inclined, you can get a used turbo on here for $200 aprox. just be sure to make sure there's no movement in the waste gate.

[JDillon15]

I know this thread is kind of dead, but I wanted to add this to it.

Forgive me!

Linkey Link (http://www.audizine.com/forum/showthread.php/565996-Wastegate-Rattle-%28Replaced-Diverter-Valve%29)