Vibration at idle

[Eddcunningham]

Morning everyone!

Hoping someone can give me a bit of advice here on my 06 GTI.
Ever since I've owned the car (jan2016), I've noticed some pulsing vibration when idling. You'll feel it through the seat and footwell for a few seconds and then it'll vanish and do it again after a few more seconds. It never used to bother me, but it seems to be happening for longer and longer these days and getting more and more violent.
I have read that these engines aren't as well balanced as you'd think, but I'm sure my symptoms are far beyond just standard vibration.

My previous experience (albeit in a diesel focus) leads me to believe it could be the DMF, by are there other things I should be looking out for?

PCV, cambelt and water pump have all been changed during my ownership.

Any help would be appreciated :)

[AJP]

This is quite common.

One theory is that the inlet side gets gunked up and the carbon deposits cause the 'hiccups'. The TFSI suffers with these deposits more than a lot of engines due to the direct injection.

You can get the deposits cleaned out - the only way of doing it properly is doing it manually. Walnut blasting is an effective means. I know Alex at AKS Tuning offers this service and he's done a few now.

However, it could be a number of other things causing it. Misfire (plugs/coils), injectors etc. It'd be worth getting a scan done to rule as much out as you can, although a slight misfire might not log a code.

I'm in a similar boat. Mine has always done it but it seems to be worse these days on a cold start, before the revs drop down to a steady 700-800rpm. Jolting, shaking, popping from the exhaust, it's all a bit rough. Once the revs settle it's all nice and smooth, with only the occasional tiny pop from the exhaust that doesn't transmit any vibration. Until recently the car behaved flawlessly under load, with Stage 2 hardware on a Stage 1 (R-Tech) map, but since I got the map updated to Stage 2 a few weeks ago I've had problems under load at full boost - fuel cuts, limp mode, and misfires at about 4k.

I'm going to approach these problems first, and see if it has any effect on the dodgy idle. I'm hoping an uprated fuel pump (Loba purchased and ready for fitting) and new coil packs sorts the problems I've had after getting the map updated. If not it could be MAF, injectors, LPFP... pretty much anything. It had new spark plugs along with the major service a few weeks ago so I can at least rule those out, in theory.

Let us know how you get on.

[Eddcunningham]

Thanks for the reply.

I've read many things out there stating that the tfsi is just a shaky engine in general, but mine does seem abnormal.
The carbon deposits would make sense though.

I'd also not rule out spark plugs as I have no idea when these were last changed, although I did have a major service (minus plugs) just last month.
I also have no idea whether the coil pack has ever been changed...

The final option is the flywheel, but with only a rumble to go on, I'd be loaved to spend around £800 (I'll get the clutch done at the same time) for potentially nothing.

[AJP]

I'd take an educated guess that it's not the flywheel.

Is the shaking worse on a cold start or a hot start? If I remember right, mine used to be worse when everything was up to temperature, but fine with a cold start. Now it seems it's the other way round. It's a strange one.

When I bought mine a year or so ago I checked with VW whether it was eligible for a coil pack recall as I knew there was one at some point. They told me no. So if I'm on the original coils at 77k there's a good chance they're failing. We didn't leave this problem with the old 1.8T it seems. TFSI coils fail all too often.

There's nothing that obviously needs attention as far as I know, since I bought it I've done the DV, PCV, cam follower, belt, water pump, two services, plugs, etc.

I really could do with getting some data logging done or at the very least a quick diagnostic scan.

It does seem to depend on who you talk to about the wobbling though. Some say 'they're just like that', whereas there's plenty of info on here suggesting something can be done about it.

[ChazGTI]

Flywheel will only show issues at idle and low revs typically.  Just replaced mine and it had much more play than the new one, even wobbled a bit!  Mine started out only making judders here and there when idling, then just became more apparent and violent over time.  Sounded like a box of gravel when i replaced it.

[AJP]

Just for info, I had a new clutch and flywheel earlier this year. Made no difference to the shaky idle, didn't expect it to really.