# Annoying noise on acceleration



## jamu (Jan 1, 2014)

Hi everyone, i hope to catch you all for a bit of advise before you get out there in the sun. When i accelerate in our 225 (normally or when in a hurry) we get a noise for a split second, i have checked the obvious heat shields (one removed) & exhaust mountings & everything is secure. The noise sounds like a contact sound but i just cannot trace it down. Any ideas would be appreciated :?


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## Pot Of Jam (Jun 17, 2011)

Is your other half in the passenger seat? Some people get a whining followed by a contact sound during heavy accelaration and have identifyed this as the cause. 

Sure someone has a better answer then this.. but I cant think of anything.


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## brian1978 (Jul 10, 2013)

Wtf is a "contact" sound :?


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## phil5556 (Feb 4, 2014)

brian1978 said:


> Wtf is a "contact" sound :?


Something hitting something.

My initial thought would be an engine/gearbox mount.


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## outdoor stevie (Nov 24, 2013)

Does it make the sound when you rev it at a standstill, and how many miles on the clock?

Stevie


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## jamu (Jan 1, 2014)

thanks for the reply outdoor steve, just been out in it today. The noise occurs just after changing gear & going back on the gas, it can also happen if you come off the gas then accelerate again, there is also a noise not unlike an ice cream van when parked & this happens when i slow down approaching an island & when the engine is hot and idling. I have had a listen through my stethoscope & the noise is loudest on the injection rail. The oil pump & oil strainer have recently been changed so i really am at my wits end.


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## WallaceTech (Nov 3, 2013)

I have been trying to nail down my sound.

Mine happens when putting my foot down, hits about 2.5k RPM, hear the rubbing sound and then boost. Its always between 2k & 3K

Does yours also happen at a set RPM?


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## brian1978 (Jul 10, 2013)

jamu said:


> The noise sounds like a contact sound





jamu said:


> there is also a noise not unlike an ice cream van when parked .


I think you win the prize for the vaguest descriptions of odd noises your car makes 

I love to help you but the only noise an ice cream van makes is a tune of some sort. If your car is doing this its very odd indeed :lol:

Can you describe it better. For example your first description would have been easier to understand of you just said it sounds like metal hitting metal when you change speed. It sounds to me like that will be a worn engine mount.



WallaceTech said:


> I have been trying to nail down my sound.
> 
> Mine happens when putting my foot down, hits about 2.5k RPM, hear the rubbing sound and then boost. Its always between 2k & 3K
> 
> Does yours also happen at a set RPM?


If it happens at a set rpm its resonating, this sounds like tge heatshield on the exhaust


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## Hoggy (May 8, 2002)

Hi, Just a guess but, Probably dogbone mount, engine/gearbox to chassis. 
Hoggy.


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## jamu (Jan 1, 2014)

Hi sorry for the late response, i think there may be two issues, the noise when accelerating is a resonating noise as if metal meets metal for a split second. If i,m really gentle when accelerating the noise will not happen but if i accelerate like a normal person the noise will occur. The second noise is after a decent run when the engine has got nice & hot, when at idle the engine sounds like a diesel engine rattle(the ice cream van at idle not plying it's trade playing the theme from the magic roundabout) & one one occasion when i restarted the engine there was a brief rattle. However this does not happen all the time so i don't know if the cam chain tensioner is on it's way out or what. I have read you can check the tensioner by removing the rocker cover & looking for signs of a leak from the tensioner. Any ideas please.


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## WallaceTech (Nov 3, 2013)

sounds like we have the same issue.

If i rev the car up and over 3k rpm without the car moving then i don't hear this rubbing sound at all. It only happens when moving.

I have noticed that during this 'rubbing noise' that it feels a little sluggish and then it boosts fine. Its one of then noises that once you hear it then it pisses you off.

I did wonder if it could be a boost leak? have you done a leak test?

Maybe between us we should come up with a list of things we have done and start to work on it together?


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## brian1978 (Jul 10, 2013)

WallaceTech said:


> sounds like we have the same issue.
> 
> If i rev the car up and over 3k rpm without the car moving then i don't hear this rubbing sound at all. It only happens when moving.
> 
> ...


Its not a boost leak, unless its a massive leak you wouldn't hear it.

Cam chain tensioner sounds like a rattle on idle. Can you record it?


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## jamu (Jan 1, 2014)

Hi Wallacetech, the noise i get is a 'vrrrr' type of noise(does not translate very well in words) & this happens at about 1500 to 2000 rpm & only happens when moving. Yesterday when i was out with my wife i noticed when i tried to accelerate there seemed to be a delay in pick up but when it did decide to go it went like a train. But i have the other noise which i believe are unconnected but my wife thinks they might be related, as for the leak test i have not carried one out but it had crossed my mind as when i accelerate i get a noise not unlike air rushing through a metal pipe. Maybe be by keeping in touch we may come up with an answer.


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## jamu (Jan 1, 2014)

Hi Brian1978, definatley a rattle on tickover best way of describing it is like a diesel engine.


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## WallaceTech (Nov 3, 2013)

jamu said:


> Hi Wallacetech, the noise i get is a 'vrrrr' type of noise(does not translate very well in words) & this happens at about 1500 to 2000 rpm & only happens when moving. Yesterday when i was out with my wife i noticed when i tried to accelerate there seemed to be a delay in pick up but when it did decide to go it went like a train. But i have the other noise which i believe are unconnected but my wife thinks they might be related, as for the leak test i have not carried one out but it had crossed my mind as when i accelerate i get a noise not unlike air rushing through a metal pipe. Maybe be by keeping in touch we may come up with an answer.


Yeah mine sounds like a dull rubbing noise. But yeah as you say a little sluggish then bang when it boosts and pulls like a train.

Your right in that it does sound like a noise of air rushing through a pipe / tube. I have done a WAK box in the last few days and the noise is definitely louder / more pronounced than it was before.

Lets keep this thread going and report back what we have found , done , checked and try and build up a picture of whats going on. It might help some of the more tech bods identify it as well.

For me.

New front tyres

New brake discs and pads all round.

Replacement DV

WAK box but issue was there before this mod. Its more pronounced with the WAK box

I don't have the rattle on start up so i think you certainly have two issues going on.


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## brian1978 (Jul 10, 2013)

If your car is sluggish then pulls well when boost comes on its probably the MAF sensor.

The noise like air russhing through a hose is normal, its just induction noise. It gets louder the more "open" the air box is. Wak box its audible, get a p-flo cone, Its like an asthmatic darth vader making a porno. 

The rattle is as I said probably the cat heat shield. Remove it.


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## WallaceTech (Nov 3, 2013)

brian1978 said:


> If your car is sluggish then pulls well when boost comes on its probably the MAF sensor.
> 
> The noise like air russhing through a hose is normal, its just induction noise. It gets louder the more "open" the air box is. Wak box its audible, get a p-flo cone, Its like an asthmatic darth vader making a porno.
> 
> The rattle is as I said probably the cat heat shield. Remove it.


Thanks mate. The sound defo is not an induction type sound. It sounds very much the like metal on metal rubbing for the period of 2k to 3k rpm. Its only when really putting your foot down If i gentle build up the speed and revs then you don't hear it at all.

My previous TT never made that noise which is why i picked up on the sound with this one. Can you clean , adjust the MAF or is it a new unit?


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## brian1978 (Jul 10, 2013)

WallaceTech said:


> brian1978 said:
> 
> 
> > If your car is sluggish then pulls well when boost comes on its probably the MAF sensor.
> ...


Yea, unscrew the bolts holding ìt in using a pair of good pliers and give it a blast of carb cleaner. The bolts are an unusual security bit. I have a 100 peice bit set and none fit it.

To be honest I personally would replace it on any TT i buy, they degrade over time and are not terribly expensive. Given how they can negatively affect performence id have a new one jyst to be sure my car was performing correctly.


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## WallaceTech (Nov 3, 2013)

is brake disc cleaner ok to use or is that a defo no no? any idea on costs of new ones mate?


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## brian1978 (Jul 10, 2013)

WallaceTech said:


> is brake disc cleaner ok to use or is that a defo no no? any idea on costs of new ones mate?


Carb cleaner leaves zero residue, use that. They are about £60 from ecp on an exchange basis with the old one.

Try unplugging yours. If it improves performance the maf is failing.


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## WallaceTech (Nov 3, 2013)

OK. Thanks mate.

I will stat with carb cleaner as its cheap to do and then if needs be will look to replace. Will start with cheap and quick first.

Will report back tomorrow with the results.


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## brian1978 (Jul 10, 2013)

WallaceTech said:


> OK. Thanks mate.
> 
> I will stat with carb cleaner as its cheap to do and then if needs be will look to replace. Will start with cheap and quick first.
> 
> Will report back tomorrow with the results.


Even cheaper, just unplug it. If will feel more responsive in low revs if the maf is goosed :wink:

I recon that 90% of TTs over 10 year old would benifit from a new MAF.


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## fixitagaintomoz (Apr 26, 2013)

jamu said:


> Hi Wallacetech, the noise i get is a 'vrrrr' type of noise(does not translate very well in words) & this happens at about 1500 to 2000 rpm & only happens when moving. Yesterday when i was out with my wife i noticed when i tried to accelerate there seemed to be a delay in pick up but when it did decide to go it went like a train. But i have the other noise which i believe are unconnected but my wife thinks they might be related, as for the leak test i have not carried one out but it had crossed my mind as when i accelerate i get a noise not unlike air rushing through a metal pipe. Maybe be by keeping in touch we may come up with an answer.


Sounds like yours only happens under load, At around the point the turbo will be starting to spool. Im making a bit of a guess here, but if the actuator is weak and not holding boost this could maybe cause the noise as the wastegate isnt being controlled properly. Have you got a boost gauge? If so disconnect the n75 and see what boost you get. My understanding is thatvif youbget less than 5psi woth the n75 discinnected then the actuator is too weak. This also explains the lack of boost then a kick. This can also be attributed to a duff n75 which dumps boost too soon.


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## Eadon (Jan 31, 2014)

I thought this noise has already been dismissed as normal with remapped cars by Wak and the like?

Maybe not the contact noise but the 'air rushing' noise is probably just different intake noises at a specific rpm.


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## fixitagaintomoz (Apr 26, 2013)

Eadon said:


> I thought this noise has already been dismissed as normal with remapped cars by Wak and the like?
> 
> Maybe not the contact noise but the 'air rushing' noise is probably just different intake noises at a specific rpm.


i dont disagree with what you are saying there- the air rushing noise id to be expected, but the OP doesnt seem to have reached an answer on this thread as to the contact noise, combined with the lack of power- this might be normal air rush noises confused, or it could be something else?

OP any joy?


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## WallaceTech (Nov 3, 2013)

I have just cleaned out my MAF with some carb cleaner i have kicking around. it was pretty dirty.

From what i read you need to leave it a couple of hours to dry. Once thats done i will pop it in and take it for a spin.


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## WallaceTech (Nov 3, 2013)

OK.

So i have cleaned my MAF and also tried disconnecting it. I have taken the car for a drive and while it has not fixed the rubbing noise it has (i think) made the car run a tad better and also seemed to be a tad punchier which is nice.


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## L33JSA (Jun 30, 2010)

fixitagaintomoz said:


> but if the actuator is weak and not holding boost this could maybe cause the noise as the wastegate isnt being controlled properly


It wouldnt make any noise it would simply underboost



fixitagaintomoz said:


> This can also be attributed to a duff n75 which dumps boost too soon.


The N75 doesnt dump boost. It can cause an overboost situation which then would cause the N249 to open the DV which then relieves the pressure

To the OP - this thread is worthless without a video/sound clip of some sort. It could literally be anything


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## fixitagaintomoz (Apr 26, 2013)

I knew what i meant about the n75.....just crap at explaining.

And then as for the noise my point is now incorrect- so ignore that


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## fixitagaintomoz (Apr 26, 2013)

I knew what i meant about the n75.....just crap at explaining.

And then as for the noise my point is now incorrect- so ignore that


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## jamu (Jan 1, 2014)

Hi all, sorry for the late response but i have been on call all week & every time i went to log on the phone went, my wife has been on the internet doing some digging around & i think she might have come across an answer. In some clips of bmw's & vw golf's they have a metallic rattling sound when revving the engine & this has been diagnosed as waste gate rattle. Has any one come across this on the bam engine, as some body previously mentioned this can affect performance & to check it requires the use of a boost guage, can some one tell me how much they are? But i still have the diesel type of noise when idling which i believe might be the cam chain tensioner, is there any way to check this before replacement as i am sure i read once that if you remove the rocker cover & start the engine if the tensioner leaks oil it is goosed. Any help would be appreciated. Thanks


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## Typhhon (Oct 28, 2006)

Sorry couldn't resist :lol:


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## jamu (Jan 1, 2014)

Just been going through old threads & a lot is mentioned about the N75 valve & dirty maf sensors, can anyone give me locations of these two items so i can check them out. Thanks


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## L33JSA (Jun 30, 2010)

Take a video clip and post it up.

Second guessing otherwise


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## WallaceTech (Nov 3, 2013)

I cleaned my MAF but no change. I will try and get. Sound bite if I can but might be hard to actually hear it.

It's very noticeable when in the car.

The MAF is in the big black pipe that comes off your air box.

Craig


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## jamu (Jan 1, 2014)

Hi Craig, as mentioned in my post this morning the metallic noise on acceleration is consistent with clips on you tube regarding waste gate rattle on bmw & vw golfs. I don't know if the waste gate is adjustable so you can take out any slack on the operating rod. Failing that i will need to obtain a boost guage & check the turbo.


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## WallaceTech (Nov 3, 2013)

Thanks mate. So we might be making progress.

Tech bods. Are there any guides or info on how to check the waste gate?


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## jamu (Jan 1, 2014)

Been out in the car today & as well as the noise on acceleration plus the diesel engine noise when warm & on tick over, there is a rattle when you start the car. I am beginning to think the diesel engine noise is being caused by a worn cam chain tensioner, can anyone confirm that by removing the rocker cover & examining the tensioner for the leaks that this is the best way to diagnose a goosed tensioner. Any ideas would be appreciated as i need to fix this as it is driving me nuts.


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## TheVarix (Apr 3, 2013)

The tensioner itself doesn't leak. Leaky cam chain tensioner gaskets (there are two) don't necessarily mean a problem with the tensioner itself. I had a leak on those and had to replace the gaskets but the tensioner was absolutely fine. As far as I know, a failing cam chain tensioner would cause a rattling noise...


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## jamu (Jan 1, 2014)

Thanks for the reply Varix, has anybody changed their cam chain tensioner?


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## L33JSA (Jun 30, 2010)

Yes it's quite an involved job.

But since you are just searching the internet with no real clue what the noise is..one minute it's the wastegate and the next its the camchain tensioner.... before you go swapping stuff out that might be unnecessary why don't you post a video clip of the noise so we can have a listen to hopefully give you more of a clue as to what it is that could be causing the noise.


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## Pugwash69 (Jun 12, 2012)

And stop chasing ice cream vans!


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## jamu (Jan 1, 2014)

Hi everyone, just a quick note regarding progress on the noises i have, today i changed the cam chain tensioner & after a sixty mile road test i am pleased to say i no longer have the noise on acceleration & no diesel engine noise on idle after the engine has warmed up. In total the job took around 3.5 hours, even before i retracted the cam tensioner there was a little free play in the chain & after fitting the new unit the chain was nice & taught. Upon close examination of the old tensioner i could see grooves in the bottom wear pad & the tensioner did not seem to extend fully.


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## LPL (Mar 4, 2011)

Wow there appears to be a lot of noisy TT's out there, mine had an engine mount issue that allowed the engine and G/box to move under acceleration, once fixed all was fine. Now I have rattle from an exhaust baffle that was easily fixed by adjusting the volume control of the Bose, Simples!!


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