1.9 tdi vibration on idle, the saga continues..

Hi all, she's an A4 130pd with around 130,000 on the clock so.. it's not the dmf, had that done almost straight away, there's an exhaust vibration on idle, sometimes a cascading rhythmic noise and sometimes a steady vibration that doesn't fluctuate at all. On raising the revs slightly the vibration completely disappears, there's another buzz between 1300 and 1500 rpm and then some weird exhaust resonance between 2200 rpm.. various so called mechanics have sworn blind it must be the DMF, (despite it having been changed, and the vibration being present regardless of being in gear or not) anyway, I digress.

Dmf and clutch has been done.

The vibration seemed to have disappeared after that, until some months later I had to investigate a rhythmic squeaking from under the car, an exhaust union was loose, tightened the bolt and voila, the car was shaking like a sh**ing dog once again.

I had the wp/tb + tensioner done lately, that seems to have made it slightly more vibey on acceleration.

Suspecting a misfire I fitted a new injector loom today and while it all seems a bit smoother that's done nothing to help the shaking on idle either.

Any input as always, greatly appreciated

I forgot to add, the vibration changes dependant on the angle of the car and temperature seems to change things a bit too, I started the car facing uphill earlier with a warm engine and there was no vibration whatsoever, I turned around to face down the hill and it sounded rough as hell.

I had considered it might be that.. mechanic said they looked ok though, plus the engine sits level and there's no knocking under braking/harsh acceleration, may as well do it though.. big job?

Wow, much to research! In my position it a eems counter intuitive to fit aftermarket mounts that transmit more vibration than oem, but I REALLY don't fancy paying oem prices! Which aftermarket engine mounts are folks running, with what kind of results?

adamss24 said:

I would look if the exhaust doesn't touch the body, it would explain why it makes noise just in one position!

Click to expand...

Thanks for all the replies guys, I wish it was as simple as the exhaust touching the body, the exhaust looks fine all the way along, mounting points look fine too but the whole exhaust system resonates at idle and at certain rpm, whether or not the engine is under load.

Dunno if it's worth mentioning but the flex joint pulses like crazy, it's not leaking though.. I know they're designed to move and all but wondering if that could be part of the issue, or telling of what the issue could be?