Vibration under load at around 2,000rpm (2.0TFSI)

[AudiAK]

Hi guys,

I am wondering if anyone can help or offer any pointers.

So I have a 2006 BWE engined 2.0TFSI A4 cab with 97k miles.

It was running really well until I had a flat front tyre and continued driving (as didn't realise til late). I replaced both front tyres and since then I have noticed a weird vibration that appears at low end speeds and around 2,000 rpm. It only happens if I hard accelerate and not if I smoothly accelerate. The vibration almost feels like the same feeling as when traction control kicks in.

Shortly after the vibration got worse and was coupled with a flashing engine management light. This was again only on load and was idling fine). Fault codes pointed to cylinder 4 and multiple misfires. I replaced the offending ignition coil and this sorted the issue but the light vibration still remained. Because I had a multiple misfire code I also decided to replace the other 3 ignition coils (as they were still originals) and spark plugs for good measure. Cylinder 1 and 4 spark plugs were worn so I thought this would fix the issue.

The car now runs better than normal but I still have this annoying vibration. I also replaced the PCV valve with a genuine Audi part (as had a Febi one before) and also replaced the air filter.

The car has no fault codes and is running perfectly otherwise. Anyone have any ideas on what else it could be?

Going back to the flat tyre and wheel change - the vibration is at low speeds like 20mph, so highly doubt it could be a buckled wheel or wheel balancing issue. Also it doesn't continue thereafter.

Any further help or pointers appreciated

 

[norad97]

Check the wheel nuts are tight, my son had this and the garage didn't torque the wheel nuts,
just a thought.

 

[AudiAK]

Hey, Thanks for your reply.

I've re-torqued the wheel bolts this morning using a torque wrench but sadly no joy.

I have also disconnected the MAF sensor plug to see if it makes any difference, but it didn't.

I did historically have a fault code pointing to the divertor valve and this has come back. However can this really cause low speed/2,000-2,500rpm vibrations?

 

[norad97]

I am a bit confused how a puncture can cause engine issues, ? I guess the car was running fine before the puncture.

Does it vibrate when coasting out of gear at the same speed.

Change the diverter valve if you have the old type, there is newer updated version.

 

[AudiAK]

The car was basically driven for about 5 miles with a complete puncture at normal speed and the driver (wasn't me at the time as I would have noticed) didn't notice the car making a noise and pulling to one side.

As it is a runaround I put new budget tyres and this may be the problem but it goes away when it goes a bit faster. The engine otherwise runs perfectly so the divertor valve or CV /driveshaft seems potential other culprits. However is it possible to damage a driveshaft whilst driving with a flat tyre?

 

[norad97]

I would have thought driving that distance on a flat tyre would have caused some issue with the wheel or bearing etc.
Have you tried changing the front wheels with the backs to confirm the wheel is fine, I assume you have alloy wheels.

I no it might sound silly, but have you checked the new tyres are fitted right, some are directional and I new someone who had them fitted
the wrong way round. Just a thought.
If all good you would need to check out the car on that side to find the cause.

 

[Baka]

Might be worth checking that your snub mount rubber is still there and in good nick, as it's an easy thing to rule out.

 

[AudiAK]

Hey All,

So just reviving my old post as I still haven't got to the bottom of this but here is where I am so far.

So as well as the vibration being under load at 2,000rpm it is also a constant vibration at motorway speeds between 70-85mph. You can literally feel the vibration in the drivers seat. Its only whilst accelerating. If I put it into neutral or am cruising it seems to drive fine.

So far I have:
- Replaced the snub mount with a new OEM one and aligned it to rule it out.
- Checked, rebalanced and changed the wheels and tyres
- Inspected underneath the car and found oil residue between the output shaft and driveshaft. I think this is residue coming from the vacuum pump but not certain.
- Inspected the wheel bearings all ok. Checked Driveshafts for play. Here if I move them side to side there isn't much but when I move them in and out, I do get a clunking/metallic noise/play. Both side shafts do this so not sure if this is 'normal' play? Anyone have any ideas?

Thanks

 

[Ricky Burrows]

Hey All,

So just reviving my old post as I still haven't got to the bottom of this but here is where I am so far.

So as well as the vibration being under load at 2,000rpm it is also a constant vibration at motorway speeds between 70-85mph. You can literally feel the vibration in the drivers seat. Its only whilst accelerating. If I put it into neutral or am cruising it seems to drive fine.

So far I have:
- Replaced the snub mount with a new OEM one and aligned it to rule it out.
- Checked, rebalanced and changed the wheels and tyres
- Inspected underneath the car and found oil residue between the output shaft and driveshaft. I think this is residue coming from the vacuum pump but not certain.
- Inspected the wheel bearings all ok. Checked Driveshafts for play. Here if I move them side to side there isn't much but when I move them in and out, I do get a clunking/metallic noise/play. Both side shafts do this so not sure if this is 'normal' play? Anyone have any ideas?

Thanks

Does the driveshafts have the metal circlip on them?

Before reading the end if your post i was thinking driveshafts there's not much else it could point to, if you can hear a clunking, clicking or knocking kind of noise in both when your moving them by hand there's definitely an issue there, take it to a garage and get them to look over it and check the deiveshafts, could possibly just need some new cv boots.

 

[AudiAK]

Finally got this sorted - it was indeed the O/S inner CV boot that was goosed. I ended up replacing the complete driveshafts for both sides for good measure (as figured the other joints would probably follow soon) and all is good as new