Help Please A4 Allroad TFSI - Flappy noise from engine when accelerating

[Audi_panda]

Hi - I wonder if anyone can help. I have a strange flappy noise (best way to describe it) when accelerating the car from around 2-3k revs. Once easing off the noise goes away. It only does this when the car is moving. Sitting on the driveway and revving the engine doesn't produce the noise.

It's coming from the engine and isn't throwing any error codes in VCDS.

I did have an error
14846 - Turbocharger Boost Control Position Sensor Circuit
P2563 00 [096] - Implausible Signal

However that has now gone away since the turbo actuator was replaced.

The air-intake manifold and crank breather have also been replaced.

The car has done around 39K miles and is a 2014.

Just wondering if anyone else has experienced anything like this. Obvs I am a bit worried the turbo is toast and is going to need replacing.

Thanks

 

[spartacus68]

Hi - I wonder if anyone can help. I have a strange flappy noise (best way to describe it) when accelerating the car from around 2-3k revs. Once easing off the noise goes away. It only does this when the car is moving. Sitting on the driveway and revving the engine doesn't produce the noise.

It's coming from the engine and isn't throwing any error codes in VCDS.

I did have an error
14846 - Turbocharger Boost Control Position Sensor Circuit
P2563 00 [096] - Implausible Signal

However that has now gone away since the turbo actuator was replaced.

The air-intake manifold and crank breather have also been replaced.

The car has done around 39K miles and is a 2014.

Just wondering if anyone else has experienced anything like this. Obvs I am a bit worried the turbo is toast and is going to need replacing.

Thanks

Unusual for the turbo to fail at 39k miles, however that said the turbo went on my 2.0 TDI at 70k on a 2012. I still think that's premature. I narrowed that down to the actuator, but on a diesel it's nigh impossible to get them separately without the right kit to set up and balance, so opted for a new Garret turbo and the actuator fitted as part of the unit. On mine, the car was going into limp mode on boost.

I did a full-strip down on the turbo and there was a bit of carbon, but not restricting movement that I could see. One of the vanes was also damaged which I was struggling to identify as to how, as there was no play on the turbine. More details here: https://www.audi-sport.net/xf/threads/435366/

One thing to note - I got the turbo replaced by a local independent. They fitted a new gasket and fitting kit and within 3k miles it was leaking oil from the oil feed union nut. Now apparently - it's fairly common to replace this pipe and sometimes difficult to get a leak-free fit. So turbo had to come back out. If you miss it and it's starved of oil, then you have bigger issues. I only noticed as it rarely used oil and engine tray had tell-tale drips afterwards, so if you are going to get the turbo - then get this feed line too.

I don't know enough about petrol version, but unless the car actually goes into limp mode - I would just continue to monitor.

 

[Audi_panda]

Unusual for the turbo to fail at 39k miles, however that said the turbo went on my 2.0 TDI at 70k on a 2012. I still think that's premature. I narrowed that down to the actuator, but on a diesel it's nigh impossible to get them separately without the right kit to set up and balance, so opted for a new Garret turbo and the actuator fitted as part of the unit. On mine, the car was going into limp mode on boost.

I did a full-strip down on the turbo and there was a bit of carbon, but not restricting movement that I could see. One of the vanes was also damaged which I was struggling to identify as to how, as there was no play on the turbine. More details here: https://www.audi-sport.net/xf/threads/435366/

One thing to note - I got the turbo replaced by a local independent. They fitted a new gasket and fitting kit and within 3k miles it was leaking oil from the oil feed union nut. Now apparently - it's fairly common to replace this pipe and sometimes difficult to get a leak-free fit. So turbo had to come back out. If you miss it and it's starved of oil, then you have bigger issues. I only noticed as it rarely used oil and engine tray had tell-tale drips afterwards, so if you are going to get the turbo - then get this feed line too.

I don't know enough about petrol version, but unless the car actually goes into limp mode - I would just continue to monitor.

Thanks for all that info - that's very useful.