Constant engine vibration developed after timing chain service - balance shafts?

[aaronkz]

First - big thanks to everyone on this forum who has been helping me out for the past ten years of head-scratching Audi ownership! But a problem so infuriating has arisen that it's coaxed me out of lurkerhood.

The intensity is pretty low, but it's driving me nuts. It's 100% an engine vibration, I believe at 2x RPM. It's particularly rough as it hits harmonics when the revs climb, and almost makes the car feel down on power. The rest of the time it's more of an electric razor feel through the wheel, shifter, pedals, and everywhere.

It appeared suddenly after the timing chain service and since then has not changed at all. I was back at the shop about 30 seconds after picking it up. They were of course unable to find anything wrong (their ideas included the, uh, snub mount, and that it's just normal) and insist that if there was a balance shaft misalignment the problem would be far worse and throw a bunch of codes.

The car does have a clutch replacement that's quite recent - from right before I bought it, so I'm unsure if corners were cut - but again, it was dead smooth from the day I drove it home until this.

Does anyone have any alternate theories?

[Spawne32]

sounds like either A) the engine is slightly out of time, which could be verified with a datalog of camshaft phase angle, or B) the balance shafts were not properly timed with the timing chain

[aaronkz]

Thanks so much! I was surprised at how little info there was on this despite hundreds of pages of timing chain content. I badgered them into taking another look tomorrow, hopefully they will crack open that lower cover without additional pressure.

[mtroxel]

Did they do the balance shaft chain? Not everyone (myself included) messes with the balance shaft chains when they do timing chain/guides/tensioner. Spawne32 is right, the cam phase angle would show a mis-timed motor. But if it was mis-timed enough to shake like that I would think your CEL is would be lit.

Don't let those assholes tell you its normal. I don't say much good about this motor but it is a very smooth runner.

[Theiceman]

Balance shafts weren’t timed properly against timing chain. Needs to be redone .


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[qmulus]

Unfortunately, BTDT and it is a pretty simple mistake to make if you are not familiar with the engine. On the first VW TSI engine I did the chains on, I did not properly time the intake side balance shaft to the idler. I didn't realize that I had turned the balance shaft while it was apart, and while I had the chain to idler correct, the balance shaft to idler timing was not right. The symptom was that there was a vibration and slight noise at idle that went away with RPMs. I would imagine that the symptoms would likely vary slightly depending upon how far off the balance shaft is.

The good new is that other than the vibration, no damage is done. The bad news is that it has to come apart again to be re-timed and there is no "quick check" to verify the balance shaft timing, no matter what someone might say.

[aaronkz]

UPDATE: The shop took everything all the way apart and claimed that everything was just fine. I was disappointed, but they took some photos for me and thanks to my forum scouring I was able to quickly verify that everything was correctly timed and in its proper place.

Then when I started up the car, the vibration was totally gone. Joy!

So I'm not asking any more questions, I'm just happy the issue is fixed. The shop has a pretty sterling reputation in the VW community so I'm glad they lived up to it. Thanks to all for verifying the issue.

[Spawne32]

UPDATE: The shop took everything all the way apart and claimed that everything was just fine. I was disappointed, but they took some photos for me and thanks to my forum scouring I was able to quickly verify that everything was correctly timed and in its proper place.

Then when I started up the car, the vibration was totally gone. Joy!

So I'm not asking any more questions, I'm just happy the issue is fixed. The shop has a pretty sterling reputation in the VW community so I'm glad they lived up to it. Thanks to all for verifying the issue.

lol if the vibration went away after they took everything apart and redid it, its because it wasn't done right in the first place.

[aaronkz]

lol if the vibration went away after they took everything apart and redid it, its because it wasn't done right in the first place.

I choose to believe that they left a 10mm socket in there and it fell out when they took it apart. I'm sure the tech was pretty stoked to find it.

[Depthcharge]

I choose to believe that they left a 10mm socket in there and it fell out when they took it apart. I'm sure the tech was pretty stoked to find it.

Haha, "THAT'S WHERE THAT WENT." Have to agree with Spawne, but since they fixed it without complaint I'd probably drive along as well.

[mtroxel]

You got the outcome you wanted, and a good story to tell. Case closed.

[Theiceman]

thought so

... of course everything is fine , after they fixed it .. believe me if everything had been fine they would have come after you for money for making them check their work, but no harm no foul , you are happy, its running well and everyone moves on.

[Slick_B8]

Sounds like a shop that doesnt do shit right and doesnt own up to their own mistakes.