TDI90: occassional wobles, shaking, vibrates at idle

Olerype

Member
My car is behaving strangely. It can drive just fine, but after a while it can start shaking when accelerating or going up a climb. Really strong and disturbing shaking. Normally just in 4 and 5th gear between 2 and 3 rpm. Disappears if going of the accelarator or de-engage clutch.

The strange thing is, that it does not behave like this always, and it can also go away just by stopping. Travelling on the autobahn in 75mph, the shaking starts after 1 hour, I de-engaged the cruise-control and pull over for 5 minutes. Then I reenter autobahn, accelerates just fine, and enable cruise control again at 75. Shaking disappeared.

Not mapped, new struts and top-mounts, new wishbones, wheel-alignment done.

Drive-shafts, diesel injectors, engine mounts, turbo variable vanes sticky? The dual mass flywheel appears fine; no noises at all. Engine pulls fine. Idle is also fine. No noise from oil chain.

Was thinking driveshafts/CV joints, but just strange that it can disappears for a while just by stopping for a short while?
 
I had similar symptoms, took it to the garage and told them to diagnose, but told them I was sure it wasn't the dmf.

They called later and said it was the dmf which needed replacing (£800). I agreed to the work after their diagnosis.

When collecting they said they also changed the inner cv joint as it was very worn out and charged me for it (£50).

I'm certain it was the cv joint all along, they did the dmf, realised the problem was still there, then discovered the failing cv joint

Sent from my SM-G930F using Tapatalk
 
The disturbingly heavy vibration under load sounds very similar indeed to the driveshaft issue I had in a previous Volvo, where the longer one of the two 'shafts had a support bearing in the middle which failed. I don't know if the A2 has a similar setup, but like you say it's also strange that it will just reset by stopping for a while.
 
My First place I would check is fuel filter, has it been changed with the last 12K miles?

Cheap to buy and relatively easy to change...

Ross
 
I would also point to it being a dry CV joint (i/e boot split and no grease left)

Inspect inner CV joints for splits or lack of relevant clips (i.e original clip or jubilee) I'd also look at this as a matter of urgency as if this is the cause it could sheer away and leave you needing recovered from the roadside.
 
I had a CV joint replaced last year which wasn't cheap. All I can describe is a general humming noise from the front of the car and it's difficult to diagnose which side until you spin the wheels off the ground.
 
Shaking/vibration is normally driveline related. Do you feel a vibration in the steering wheel? A vibration in the steering wheel tends to indicate the issue is located nearer a wheel, and not towards the engine/transmission, where the whole car would be affected and it would be isolated/contained by the engine/transmission mounts.
I agree with all the above regarding CV joints, but the intermittent part doesn't follow logically. The vibration under acceleration and stopping when stepping on the clutch or letting off the gas could easily be CV joint related, but it doesn't explain your "fix" by waiting 5 minutes. And as stated, worn CV joints tend to "hum/rumble", but not intermittently...

I had a almost similar situation with my Passat station wagon when driving on the motorway, I could get a vibration from the right front wheel that seemed to get worse if you didn't slow down, and I would pull off the road to check if the wheel felt loose (lug nuts??). Finding nothing wrong, drive away to find that the vibration was gone. And it could happen again 2 weeks later... The first time it happened to my wife, and after I came and swapped cars with her, I drove home with out any vibration what so ever... :)
It turns out that the brake pistons on the right front caliper were sticking, and the brake pads were dragging on the ventilated disc to the point that it was so hot that it would warp/distort and vibrate between the pads. And the use of the brakes to slow down and plus the time used to check the wheel, allowed it to cool down (restore to the correct form), and also may have helped the pistons loosen somehow. So the vibration was "fixed".
So the next time you experience the vibration, pull off the road and feel the center area of your wheel/rim to see if it is hot. I found out my problem just by being near the wheel/rim when I tried to shake the wheel to see if it was loose. Do not touch the disc directly, because if a warped disc is the problem you can be severely burned. You might compare all 4 wheels/rims to see if there is any difference. My wheel bearings survived the heat, but you might check yours if turns out to be the problem and you have had it for a while.
 
Shaking/vibration is normally driveline related. Do you feel a vibration in the steering wheel? A vibration in the steering wheel tends to indicate the issue is located nearer a wheel, and not towards the engine/transmission, where the whole car would be affected and it would be isolated/contained by the engine/transmission mounts.
I agree with all the above regarding CV joints, but the intermittent part doesn't follow logically. The vibration under acceleration and stopping when stepping on the clutch or letting off the gas could easily be CV joint related, but it doesn't explain your "fix" by waiting 5 minutes. And as stated, worn CV joints tend to "hum/rumble", but not intermittently...

I had a almost similar situation with my Passat station wagon when driving on the motorway, I could get a vibration from the right front wheel that seemed to get worse if you didn't slow down, and I would pull off the road to check if the wheel felt loose (lug nuts??). Finding nothing wrong, drive away to find that the vibration was gone. And it could happen again 2 weeks later... The first time it happened to my wife, and after I came and swapped cars with her, I drove home with out any vibration what so ever... :)
It turns out that the brake pistons on the right front caliper were sticking, and the brake pads were dragging on the ventilated disc to the point that it was so hot that it would warp/distort and vibrate between the pads. And the use of the brakes to slow down and plus the time used to check the wheel, allowed it to cool down (restore to the correct form), and also may have helped the pistons loosen somehow. So the vibration was "fixed".
So the next time you experience the vibration, pull off the road and feel the center area of your wheel/rim to see if it is hot. I found out my problem just by being near the wheel/rim when I tried to shake the wheel to see if it was loose. Do not touch the disc directly, because if a warped disc is the problem you can be severely burned. You might compare all 4 wheels/rims to see if there is any difference. My wheel bearings survived the heat, but you might check yours if turns out to be the problem and you have had it for a while.
I had similar problems, after much searching it was the brake sticking that caused judder. ....worth checking
 
Drive train. Anywhere from buckled or loose wheel through bearings, cv joints, final drive, clutch and DMF. Could also be sticking caliper, weak or broken spring, weak or broken shock absorber.........
 
Last edited:
This one remain unsolved.

New parts:
1) new diesel filter
2) two of the engine mounts are replaced
3) injectors inject equal amounts of fuel

New observations:
4) the engine shakes also on idle, but just occassionally as sometimes it run as normal
5) sometimes the shaking disappears just by turning ignition off and on again
6) when the engine shakes it shakes so heavy that the engine mounts are not able to absorb the forces so the «rubber stops» of the gearbox-engine mount touches the frame and causes the car to shake
7) engaging or disengaging clutch when idle does not make any difference

Video when running normal:

Video when shaking:
 
Back to @spike solution a failing or intermittent injector loom is very possible. Only other thing I can think of is poor engine earthing, try running a second temporary earth from the chassis to the engine. Quick and easy to try. If the shaking now stops then you will either need to renew existing earth or run a secondary one. A faulty tandem pump could starve fuel or let in air causing the misfire shake.
 
Back
Top