Multivan vibration query

[Silver Caravelle]

What is the engine idle speed?
It should be 700-850 rpm

The engine speed is spot on within that range (approximately 750 to 800). And hasn't altered since new (12months). What has altered is the vibration/pulsing feel. Can be felt in Drive or Reverse when stationary/pulling up a the lights etc, but does vary in terms of significance.

Cheers,

Scott

[gregozedobe]

Is there any chance the vibration is being caused by a DPF regeneration ? If you do lots of stop-start driving (eg heavy traffic) and/or short trips the soots builds up in the DPF more, so the ECU runs more frequent regenerations to burn off the soot. Most people don't notice a regeneration when they are moving, but it supposedely makes the idle a bit rough (and smells very hot).

Do you still get the vibration if you select neutral when going along at a reasonable speed (looking for clues as to the source of the vibration - engine or drive train).

If it was a manual I'd be looking suspiciously at the DMF, but yours is an auto so it can't be that.

Driveshafts are another potential source, but only vibrate when you are moving (or trying to move when they're completely gone).

[Silver Caravelle]

Is there any chance the vibration is being caused by a DPF regeneration ? If you do lots of stop-start driving (eg heavy traffic) and/or short trips the soots builds up in the DPF more, so the ECU runs more frequent regenerations to burn off the soot. Most people don't notice a regeneration when they are moving, but it supposedely makes the idle a bit rough (and smells very hot).

Do you still get the vibration if you select neutral when going along at a reasonable speed (looking for clues as to the source of the vibration - engine or drive train).

If it was a manual I'd be looking suspiciously at the DMF, but yours is an auto so it can't be that.

Driveshafts are another potential source, but only vibrate when you are moving (or trying to move when they're completely gone).

Hi gregozedobe,

Thanks for the suggestions. I know it is not the DFP regeneration that is causing the vibration for the following reasons. Firstly the DFP regeneration occurred on the weekend during a country run. It tends to occur about every 6 to 7 weeks dependant on my driving cycle. You can sort of hear the turbo making sorts of whoosping noises (with some engine surge) at lowish revs during DFP regeneration. And as you indicate smells very hot. Secondly, the 'vibration' has only occurred since I first raised this post.

The vibration is not evident in neutral when going along at a reasonable speed.

I am still leaning towards an engine mount (may be a very slighty loose mount), but was not able to convince the dealer. They appear to not think there are any issues with the engine mounts. My previous T4 Caravelle had engine mount problems that were only detected with the mounts removed and fully examined - show signs of internal fatigue. One would hope it isn't mounts after only 10,000 to 15,000KMs!

The Dealer mentioned the EGR can cause rough running, but I would not have thought when idling as the EGR is supposed to be closed at idle. In any case idle is smooth/stable.

Drive shafts feel tight and do not appear be showing signs of any slip/play. Perhaps I should somehow explore this one further though

No obvious signs of exhaust issues.

Thanks again for your suggestions. I might have to wait to see if it gets worse over time before it can be isolated.

Regards,

Scott

[gregozedobe]

Maybe worth pulling off the bottom engine cover and getting a pry bar in to see if the engine moves much on the engine mounts - if it does then you have some concrete info to present to your dealer. It is unfortunate, but many dealers seem reluctant to do any warranty work without a bit of prodding (maybe VWA pay rates are too low ?). So many times you hear of people being fobbed off with the old "they all do that, it is just a characteristic of the vehicle" line, when they don't, there is something wrong that needs fixing. Thankfully my dealer (Lennock motors) doesn't usually do that to me.

[Silver Caravelle]

Maybe worth pulling off the bottom engine cover and getting a pry bar in to see if the engine moves much on the engine mounts - if it does then you have some concrete info to present to your dealer. It is unfortunate, but many dealers seem reluctant to do any warranty work without a bit of prodding (maybe VWA pay rates are too low ?). So many times you hear of people being fobbed off with the old "they all do that, it is just a characteristic of the vehicle" line, when they don't, there is something wrong that needs fixing. Thankfully my dealer (Lennock motors) doesn't usually do that to me.

I hear you and couldn't agree more.

I was hoping not to be crawling under a 12 month vehicle and have got to a point in my life where I couldn't really be bothered Yep, best I get inspired and drag the overalls out of the cupboard to check it out for myself. The whole arrangement looks at least from under the bonnet much more complicated than the T4 Caravelle.....with the subframe mounts and engine mounts etc.

Cheers,

Scott

[Transporter]

Have you done any modificatios to the van - chip, reflash?
Also the dual mass flywheel can cause wibration.

[gregozedobe]

My 10 month old auto tdi Multivan has in recent weeks developed some increased (although minor) vibration when in drive at idle.

Also the dual mass flywheel can cause wibration.

I don't think T5 autos have a dmf (they have a torque converter instead, as they are a conventional auto).

[Transporter]

Oops, I did read the first post properly than, almost posted a question if it was auto or manual.

[Silver Caravelle]

No mods, just bog standard.

Hope its not the bloody torque converter loading up a little too much causing it!

I will attempt to check the mounts.

Thanks and Cheers,

Scott

[Transporter]

It's quite possible mate. Another one to check out would be the timing gears. If you have a stethoscope you could narrowed down.