2002 A4 problem

[stevey_boy]

Recently i have noticed a chattering sound coming through the air box when i take my foot off accerlator on my 02 audi a4 1.9 tdi sport, i took my car to an ex audi mechanic and he said it was the turbo on the way out but recently be advised it cant be the turbo as there is no loss of power or smoke form the exhaust. However there is a slight hestition on accelerating sometimes.

As anyone ever has such a problem or know what this might be?

btw the car has 123k miles on the clock and been remapped

Thanks Stephen

 

[simon.m]

when you say chattering is it like a rattle like some thing is lose? and is it doing it under load only or all the time i ask as i have a rattle kind of sound
when i change gear some times thought it was a heat shild or some thing as i dont have smoke or any other problem with power and was hoping its not the turbo bearings

 

[blucoop]

i had this on my old car.

it was a split vacuum pipe that goes onto the dump valve. £10 fix. ;-)

although may not be same problem but worth a check!

 

[simon.m]

where abouts is it mate

 

[blucoop]

sorry not sure about your problem mate. i was reffering to the first post. The vacuum pipe that went onto the dump valve had perished, causing a rally car style chatter, and some hesitation when accellerating.

 

[simon.m]

oh right i was thinking we may have the same problem but what i think is a rattel maybe a chatter

 

[J7USS]

Id say Boost Leak!

 

[stevey_boy]

thanks for the reply guys! yea its like a turbo flutter kind off noise

whereabouts is the hose coming off the dump valve?

 

[J7USS]

Not sure of the location of the Valve (...never knew the TDi had one to be honest) but id just check all pipes coming from your turbo and surrounding it. Though mine is a 1.8t, ive had 4 boost leaks and getting pretty quick now in finding them.lol

 

[stevey_boy]

thanks chum, also my econ light is staying on all the time would this have anything to do with it?

 

[simon.m]

no the econ is the aircon mate maybe low on gas

 

[stevey_boy]

yea thought that just the two appeared at the same time

 

[simon.m]

thats what we call luck lol

 

[slepy]

stevey_boy is that sound when you release accelerator and you can hear it best under 2k rpm?
Didn't you change oil for fully synthetic not long ago? Is the sound coming from the air filter box?
If you replied to this questions YES than the answer is NO ONE KNOWS WHAT IT IS.
I haven't found much info on any uk forums about that but there is about 40 pages thread on polish one.
The sound comes on most of the time after changing oil to fully synthetic from semi one.
There are people who changed EGR, N75's, Turbo's and everything else that is possible and in most cases sound stayed after that.
Few people say that it disappeared after changing turbo but there are some that it didn't help either.
All I can tell you is that there is loads of people who did more than 60k miles with that sound and nothing happened.
I've been to VAG specialist, Audi main dealer and 2 other mechanics and none of them can find out what it is.
I don't have any power loss and did already 15k miles with that.
Oh and one more thing. Some people tried to find out if the same happens to other VAG cars with 1.9Tdi other than AWX code and... it doesn't

 

[simon.m]

slepy im thinking i have the same problem iv had it for around 4 mths now i though it was like i rattil from a heat shild but it dose sound like its coming from by my feet in the car
so ie turbo so i was thinking it maybe bearings or some thing as like you say i get it just on changing up in gears from 1st upto 4 and under 2k revs iv taken it down the
motor way and can not hear it at all or evan at 30 40 or 50 mph it is just on changing gears. im thinking mine needs a oil change so ill do that and see if it helps.

 

[AudiLeon]

Chatter suggests to me Turbo stall. Which is down to the wastegate not opening and air bouncing back through the blades.

 

[simon.m]

is there a way of fixing this blackquat

 

[slepy]

simon - oil change will not help, I've just done mine few weeks ago

 

[simon.m]

ok needs doing any way ;-)

 

[stevey_boy]

slepy yes that's excitly how it is! gona take it to mechanic again wed night, it's like a rasping sound and sounds like it could be doing damage I duno!

 

[slepy]

Let me know if you find out something. Whole world is waiting ;D

 

[stevey_boy]

ok i went back to my mechanic and he says its defo the turbo! I also went back to the guy who remapped the car and he says theres no way its the turbo but could be the air flow sensor, so its booked in to be put on the rolling road and see whats up! Also might think about taking off the EGR valve and giving it a clean even tho it was replaced a few months back

 

[slepy]

It's defo not EGR or N75 mate. Loads of people had it changed because of that sound and no good result...

 

[brownie 25]

i just rebuilt my engine its a 2.5 tdi there was a similar noise coming from my air box kinda like a scooby if that makes any sense,hopefully this is not the same problem you have cause if it is its your hydraulic tappets are seized, i replaced a good few of them and it runs perfect no noise.