Vibration Under Mild Acceleration

[Lambda13]

Hey guys, been having some issues... ok a lot of issues lately, but most of those are for a different thread and another time. I'm trying to figure out what is causing my car to vibrate under mild acceleration. Gentle and harsh acceleration don't reproduce this issue but if I keep a consistent mild acceleration I get a vibration in the peddles and throughout the rest of the car. Not enough to shake things around much but definitely noticeable. Car runs reasonably well otherwise.

A side note to this is that when coasting to a stop I get a ticking noise that is similar to a baseball card in the spoke of a bike tire like we did when we were kids.

A second side note is that my car will not break 20 PSI.

My Car:
09 A4
APR K04
EC FMIC
AWE exhaust
APR intake
6 speed TIP

Recent maintenance:

Timing chain tensioner
Oil pan
Trans fluid drain
Rear diff fluid
Coolant flush
Carbon clean
Fuel injectors
Fuel filter
High pressure fuel pump
Spark plugs

Any potential ideas or fixes would be greatly appreciated. I'm getting so sick of this car not functioning properly.

[Project Quattro]

Did you make sure that you left your toys in the bedroom?


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[Mussa]

That ticking noise while coasting is 99% from a loose wastegate.

[Project Quattro]

Wait I just reread this and am done making jokes... you still can't get above 20PSI with a K04?

Re: the vibration, did you replace that motor mount yet? Could easily be causing the engine to move more than normal... under high acceleration it could torque so far over that the vibration goes away, under light acceleration it may not twist the good mount enough to vibrate.

[jmeenach]

Wait I just reread this and am done making jokes... you still can't get above 20PSI with a K04?

Re: the vibration, did you replace that motor mount yet? Could easily be causing the engine to move more than normal... under high acceleration it could torque so far over that the vibration goes away, under light acceleration it may not twist the good mount enough to vibrate.

Could explain vibration, but I wonder what the low boost is from?

[jfo]

I have a similar vibration and have been thinking motor mount. It's only noticeable when the engine is labouring a bit, going uphill at low rpm and before it kicks down. Normal or hard acceleration is fine.

[Project Quattro]

Could explain vibration, but I wonder what the low boost is from?

He's had this basically since the K04 went on, and maybe even longer.


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[prkieffer]

Motor mount, tranny mount, and lower rearward control arm bushings are culprits for vibration in 09.


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[Militant-Grunt]

Production Solution

Updated front wishbone links are equipped with larger (75 mm) fluid-filled bushings that help dampen steering wheel oscillation.






Wishbone links are available with two different size ball joints that are not interchangeable. If the vehicle is equipped with the original wishbone links that have the smaller 65 mm bushing, use the VIN to search ETKA to determine the size of the shouldered hex nut (Figure 4, point 6). Use the shouldered hex nut size to determine the correct wishbone links from the Required Parts table.








8K0498998 (Kit) includes:


8K0407693R - Left wishbone link – M12
•
8K0407694R - Right wishbone link – M12




8K0498998A (Kit) includes:

8K0407693S - Left wishbone link – M14
•
8K0407694S - Right wishbone link – M14

[Lambda13]

That ticking noise while coasting is 99% from a loose wastegate.

Normally I'd agree with you but this is different than the wastegate issue I had with my K03. I'm very familiar with that sound as it was about 25% of the reason I went to the K04. This is more of a sharper sound that actually changes pace depending on the speed of the car. When it was the wastegate on my K03 it was the same frequency and was independent of speed.

He's had this basically since the K04 went on, and maybe even longer.


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I used to regularly hit 26 PSI when I got my K04 originally.

Production Solution

Updated front wishbone links are equipped with larger (75 mm) fluid-filled bushings that help dampen steering wheel oscillation.

Thanks for this info, but it's not just the steering wheel unfortunately. Its almost like the entire car is shuddering.

Side note, yes my engine mounts are shot but I feel like that wouldn't be affected by acceleration?

[Project Quattro]

Side note, yes my engine mounts are shot but I feel like that wouldn't be affected by acceleration?

Could be, I kind of outlined my thinking above. The engine definitely moves under load, especially with the power you're putting through it.

Under high acceleration it could torque so far over and press against the mount so that the vibration goes away, under light acceleration it may not twist the mount enough to vibrate.

[Militant-Grunt]

Normally I'd agree with you but this is different than the wastegate issue I had with my K03. I'm very familiar with that sound as it was about 25% of the reason I went to the K04. This is more of a sharper sound that actually changes pace depending on the speed of the car. When it was the wastegate on my K03 it was the same frequency and was independent of speed.



I used to regularly hit 26 PSI when I got my K04 originally.



Thanks for this info, but it's not just the steering wheel unfortunately. Its almost like the entire car is shuddering.

Side note, yes my engine mounts are shot but I feel like that wouldn't be affected by acceleration?

If the engine mounts are shot, and you know this for a fact, I would start with that and continue with your diagnosis. If a problem isn't clear cut, you need to start with the obvious.

[jmeenach]

If the engine mounts are shot, and you know this for a fact, I would start with that and continue with your diagnosis. If a problem isn't clear cut, you need to start with the obvious.

+1

[Lambda13]

If the engine mounts are shot, and you know this for a fact, I would start with that and continue with your diagnosis. If a problem isn't clear cut, you need to start with the obvious.

+1

There's no way I'm gonna spend another $500 unless I can 100% confirm those are the issues. On the fence with just straight parting the entire car at this point. I've had enough bullshit to last me a few years at this point.

[Militant-Grunt]

There's no way I'm gonna spend another $500 unless I can 100% confirm those are the issues. On the fence with just straight parting the entire car at this point. I've had enough bullshit to last me a few years at this point.

Thats the German car life. Got to pay to play son. If you can't keep up get a honda.

[Lambda13]

Thats the German car life. Got to pay to play son. If you can't keep up get a honda.

If I told you what I've paid in maintenance in the last 6 months you'd be sick. Trust me I'm familiar, but thanks for the reminder lol

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[Militant-Grunt]

If I told you what I've paid in maintenance in the last 6 months you'd be sick. Trust me I'm familiar, but thanks for the reminder lol

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Shame you're not in the NYC area, my rates are reasonable

[Lambda13]

Shame you're not in the NYC area, my rates are reasonable

Haha good to know. I'm down that way occasionally. I do most of my own work, unless it involves a lift...

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[AllroadCorbin]

Andrew shot engine mounts are also really bad to just hold onto. Puts unnecessary strain on shit. If they're shot they need to go. Ill sell you my 034 mounts and swap in some stock ones eventually. You'll have less NVH than you have now lol. They still are annoying but at least you'll know your mounts are holding down the fort like a mofo. On that note, I read somewhere that shot mounts and excess NVH can actually trigger the knock sensors to think its pre-detonating. Again I only read this on this or perhaps Vortex so not sure if that's total bullshit. But I agree, if it's broken they need to go. Remove the obvious broken issues. Also- let's finally log your car with the VAGCOM sitting in our garage and look for timing retard or low N75 duty. Let's get some data we can post on here for folks to inspect, instead of some theories written on a cocktail napkin


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[Project Quattro]

Haha good to know. I'm down that way occasionally. I do most of my own work, unless it involves a lift...

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Swap the mounts. It's worth it. You like that car and once you get though these 100k mileage-related repairs it should serve you well for a while.


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[AllroadCorbin]

Swap the mounts. It's worth it. You like that car and once you get though these 100k mileage-related repairs it should serve you well for a while.


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I think it's got another 50k in it easily. I'm hoping to get 175,000 out of mine without much fuss.


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[b6Hate4]

If you are looking to spend the least amount of money to figure out what the issue is then just drop it off to a shop and have them figure it out, otherwise you're likely to replace more than a couple fairly large ticket items before finding the culprit of this issue.

[Lambda13]

If you are looking to spend the least amount of money to figure out what the issue is then just drop it off to a shop and have them figure it out, otherwise you're likely to replace more than a couple fairly large ticket items before finding the culprit of this issue.

I'm thinking you're probably right. I may have to do that...

[Liquid Smoke]

sounds like it's the mounts, the engine definitely shakes more when accelerating. i would say check the front lower curved control arms too, those are known to go bad on the 09s, i had to replace mine for vibration too, and about to do mounts next.

Shame you're not in the NYC area, my rates are reasonable

just followed you on fb, will have to keep you in mind. where in nyc?