1.2TSI crackling/buzzing sound

[Ant83]

Hi, I've recently bought a used 2015 1.2TSI fabia and have a very irritating buzzing sound I can't find the source of, please help!

 

- I can't hear it when idling, but as soon as I push down on the throttle it starts and doesn't stop until I release the throttle fully (even maintaining a constant speed I can hear it unless I take my foot off the throttle).

- It isn't related to the air con (I hear it even when the air con and fans are turned off)

- It isn't related to engine temperature; it's just as loud after a 2 hour drive as it is when I'm first pulling off

 

I've attached an audio recording, with my phone placed in a mount attached to the windscreen. The recording starts when I'm stopped at some lights about to turn right. The mic hasn't captured the buzzing very well, but you can hear it fairly clearly from 9 seconds in. You might mistake it for bad audio quality as it sounds like a crackling/buzzing and isn't very loud compared to the other sounds (engine, road & noise). It's louder in real life than it sounds on the recording though.

 

Has anyone experienced this?

20210606_131104_1_1.mp3

[rum4mo]

Sorry but I can't hear anything out of the ordinary.

[Ant83]

33 minutes ago, rum4mo said:

Sorry but I can't hear anything out of the ordinary.

 Hi, I've run the audio through a high pass filter to reduce the engine and road noise somewhat. If you listen to the latest attachment you can hear it clearly. It sounds like static from a bad mic but it isn't, it's the sound my engine is making.

highpassfilter.wav

[Ant83]

From 9 seconds in I'm no longer accelerating, just driving at a constant 30mph so it's easiest to hear from then on (e.g. without the sound of the engine accelerating getting in the way).

[FabiaGonzales]

Honestly can't hear anything out of the ordinary, sounds a lot quieter than mine that's for sure haha

[Eccles]

My car is also 2015 1.2 TSI. I can just about hear your recording but nothing that I would worry about, "nasty" noises are usually far more strident. Perhaps the radio is on but "off station" which can sometimes produce such effects.

[rum4mo]

All I can offer is, and this is not based on the actual noise on your recording but based on the fact that you are hearing it when driving on a light throttle at a steady speed - under these conditions, the EVAP valve will be getting pulsed to clear out any vapour gathering in the petrol tank - my wife's 2015 Polo 1.2TSI 110PS used to make a lot of "peeping" noises that I got sorted by demanding that VW dump the plastic ribbed EVAP hose and fit the later smooth bored rubber hose - that worked.

[Aviii]

Is it a rattling sound that happens under light acceleration if you're holding out the revs a little bit?