whirring/chattering noise when foot's to the floor

[m8arx]

recently i've been getting a whirring noise/chattering noise when i have the foot to the floor in my s3. the turbo was not long reconditioned, and all gaskets were replaced when it was put back in.

I've not heard the noise from outside the car, but my mate says it sounds like a blowing noise - i've checked the pipe's for leaks and cracks but honestly can't see anything.

anyone got any idea's what it could be?

 

[s3dave]

If it does it on maximum rpm it will be hard to find, but will be a leak somewhere, ideally you need to leak test under pressure to find the culprit

 

[m8arx]

nah it does it whenever the foot is to the floor (or at least 3/4's of the way down) from about 2000rpm onwards, if you give it half boost the noise isn't there, it's only when you have the foot more or less all the way down.

 

[m8arx]

and to think this was a forum to help other a3/s3 owners - makes me wonder why i registered sometimes.

 

[reptor245]

and to think this was a forum to help other a3/s3 owners - makes me wonder why i registered sometimes.

Way to go dude.....

You got your answer in the first reply. Do a pressure test.....

If it does it on maximum rpm it will be hard to find, but will be a leak somewhere, ideally you need to leak test under pressure to find the culprit

 

[m8arx]

and i replied saying it doesn't do it at full RPM - if you read it correctly "dude" you'll see that.

it does it when you accelerate and have your foot more than half way down

 

[Dani_B19]

This is a forum to try and help a3/s3 owners but we arnt audi, you have to understand people on here arnt all experts, yes there are one or two people who are but the rest of us learn as we go.

Have you pressure or smoked tested the car? Do you have access to vag com to log the car to see id there's any fault codes? Have you checked all pipes, ie n249 vac lines, under the inlet manifold etc?

 

[thorsy22]

Answer is still to do a pressure test for leaks, find one fix it, if it solves the problem all well and good, if not reply again saying that theres no leaks what else could it be.

B1tching that more than one person didnt reply is not going to make you friends or get you help. Did you stop to think that the one reply might of been the correct one and the reason you didnt get more responses was the answer was already posted?

 

[m8arx]

i know that, but there must be someone else who has had a similar problem.

I don't even know if it is a boost leak - would a boost leak create a "chitter" sound?

i don't have access to vagcom, i've checked all pipes that i have access too and can't see/feel any cracks/holes.

 

[reptor245]

and i replied saying it doesn't do it at full RPM - if you read it correctly "dude" you'll see that.

I did read that "Pal" but becuase no-one replied in 24hrs you then replied again with

and to think this was a forum to help other a3/s3 owners - makes me wonder why i registered sometimes.

Sometimes posts dont get a reply for days till someone who has the answer is online. Word of advice, If you want a answer in a split second then try ringing your local dealer.
People have said to check for a boost leak. have you done that??

 

[m8arx]

Answer is still to do a pressure test for leaks, find one fix it, if it solves the problem all well and good, if not reply again saying that theres no leaks what else could it be.

B1tching that more than one person didnt reply is not going to make you friends or get you help. Did you stop to think that the one reply might of been the correct one and the reason you didnt get more responses was the answer was already posted?

the reason i bumped it it because s3dave said to do a pressure test if it was happening at max rpm - which it ISN'T and i had replied saying it wasn't and got no more replies.

so you're certain it's a boost leak then? whats the best way to do a pressure test?

 

[m8arx]

I did read that "Pal" but becuase no-one replied in 24hrs you then replied again with

Sometimes posts dont get a reply for days till someone who has the answer is online. Word of advice, If you want a answer in a split second then try ringing your local dealer.
People have said to check for a boost leak. have you done that??

like i said "bud", i've checked all pipe's that i can access and can't find any cracks/hole's.

my point is, surely a boost leak in a rubber pipe wouldn't give off a chattering sound, it would be a blowing noise would it not?

 

[reptor245]

Good luck "Mate"

 

[m8arx]

cheers "chum"

 

[Dani_B19]

Are you running a standard dump valve? If that goes or sticks it can create a sort of chatter noise, my forge one dried out and started giving a similar sound, regreased it and its been fine!

 

[s3dave]

pressure test is to pressurise the system with a compressor at around 15 - 20 psi usually you take the maf off, and put a cap in with a valve, you can do it with a spare tyre too, i think you have to block the pvc line somewhere so you dont get bubbling oil from the sump

chatter is usually the turbo stalling, slicing the air up, not to good for the bearings, maybe a faulty bov or associated pipework look closely at the one that goes to the actuator

 

[s3dave]

recently i've been getting a whirring noise/chattering noise when i have the foot to the floor in my s3QUOTE]

sorry thought you meant you were redlining, it with that comment....

 

[m8arx]

ok - an update.

it doesn't do it when cold/warming up (and no, i didn't boot the **** out of the car from cold)

like i've said before when you have the foot down and it's just coming on boost, thats when you hear the noise but it definately doesn't do it when it's cold/warm, so this would suggest to me it's not a boost leak (because it should happen at all times if it was a boost leak, hot or cold/warm) and possibly something on the manifold side causing problems/blowing?

or am i talking pants?

 

[MUSH]

boost leaks can show themselves at any pressure rating, it just depends at what point there is a fault and how that reacts to certain pressure applied. so yes you may get boost leaks at certain points but they may not show themselves at full chat. Do you have a boost guage? if there is a leak and the map sensor sees it then you may think you are making full boost but the actual boost is being held back, beyond the point of leak.

so, a real pressure test as described above really is the way forward, with particular attention, as described above to the known weak points (dv, n249, any other vacuum pipes).

that aswell as a scan with vagcom should point you in the right direction. if theres codes for boost loss, for e.g. 17705, then it would be beneficial to log requested boost vs. actual boost to see how much is lost.

The most common cause for what you are describing would be the dv, it can create boost loss and turbo stalling situations which as again said above, aint to good for the turbo shaft bearings/seals.

 

[Matt82]

in a minute the penny is gonna drop and hell pressure test it haha

 

[Welly]

with everyone above.

As everyone knows, metal things expaannnnddddddd when they get hot.

So - metal jubilee clips for example, expand as they get hot.

All your boost hoses are held on with jubilee clips.

Leaks occur in the charge system when there is a gap available to allow air to escape.

Rubber hoses, such as the ones in your charge system, also become more pliable when heated.

So lets put the above together shall we?

Engine cold = nice tight pipes and connections. Engine hot = Much more chance of a boost leak.

For the millionth time, start with the obvious things get it pressure tested.

DV is also a real possibility.

 

[Dazboss]

Hmmmm least ive learnt something out of this post, My cars been acting the same lately. Thought it was the exhaust down pipe gasket but might not be.

 

[m8arx]

with everyone above.

As everyone knows, metal things expaannnnddddddd when they get hot.

So - metal jubilee clips for example, expand as they get hot.

All your boost hoses are held on with jubilee clips.

Leaks occur in the charge system when there is a gap available to allow air to escape.

Rubber hoses, such as the ones in your charge system, also become more pliable when heated.

So lets put the above together shall we?

Engine cold = nice tight pipes and connections. Engine hot = Much more chance of a boost leak.

For the millionth time, start with the obvious things get it pressure tested.

DV is also a real possibility.

i love sarcasm

anyway, i fitted a boost guage this morning to see whats going on. i don't have access to anywhere to do a pressure test so i'll be checking all pipework when i get the chance.

when i get the chatter noise, i only get 0.8 bar and doesn't go any further. when the noise doesn't happen, i get full whack of boost.