loud rattling noise when accelerating
 

Hi everybody,

I have a 1.8 T engine on a Audi TT, 225 HP, 2000.

I was on the way to order a new Oxygen Sensor (see my Oxygen Sensor topic) and suddenly, in 2nd or 3rd gear instead of hearing the turbocharger noise I heard a rhythmic noise in the engine compartment, a kind of rattle or propeller noise that is touching something. I don't know if the turbocharger sound is still present or not because the new noise covers it. I suspect that the sound is produced by I broken valve.

- I can only hear the noise when accelerating, when I push hard the pedal.
- If I press the throttle gently and constant, I do not hear the noise.
- In 1st and second gear I can go above 4000-5000 rpm but in 3rd and 4th I have a lack of power; at WOT the rpm hardly grow above 3000.
- I cannot hear the noise while the car is not moving, no matter the rpm.
- I have inserted under pressure air into the admission system. I have discovered that a hose between the pressure valve and the admission tube had a small crack at one end. I have replace it. I have also discovered a exploded hose between the engine and admission - used for oil gas recirculation. I have replace it either. The noise is still there though!
- I have checked the DV. It's fine.
- There is no blue smoke coming off the exhaust, hence the turbocharger seems to be ok.

What else should I check? What can produce the noise?

same problem has an one help u out yet with this