Shaking when idle at 700 RPM. Normal?

[Raven105]

New guy here. Just bought a B8.5 S4 and i absolutly love it. Wondering if its normal that my car idles between 600-700 RPM and there's some minor shaking. I noticed on startup its at 1200 and then slowly drops, once it gets below 800 the shaking starts.

[SwankPeRFection]

It's somewhat normal. Doesn't always happen. There's a new ECU update from Audi that was released for early B8 S4 cars that addresses these issues, but I haven't experienced the new update to tell if it really solves it. Honestly, it's not that intrusive. It tends to seem to happen if you've been babying the car for a few days and then start it cold one day and let it idle down from the fast idle. Seems driving the snot out of it a few times and no more issues. Makes me wonder if it's not just slightly fouled plugs because of the heat range they run on these cars.

[Raven105]

Thanks. Sounds like its nothing to worry about. Maybe ill just mention it to the dealer next time I stop by.

[Leor604]

90 degree V6. Will never be as smooth at idle as an I6 or 60 degree V6. Normal.

[Dr GP]

For some reason the idle seems to vary from around 750-800 rpms. When the rpms get lower than 800 there is some roughness. Nothing wrong with the car.

[Raven105]

For some reason the idle seems to vary from around 750-800 rpms. When the rpms get lower than 800 there is some roughness. Nothing wrong with the car.

I was just out for a drive and kept a close eye on rmp at idle. It's idling at 625-650. Is that still normal or a little low? I just bought her last week as a certified preowned with 16000km(10000mi).

[shappy]

I noticed that my S4 does this too. The idle is rock steady, but I can feel shaking in the seat and shifter when I am sitting at a light.

[SwankPeRFection]

I was just out for a drive and kept a close eye on rmp at idle. It's idling at 625-650. Is that still normal or a little low? I just bought her last week as a certified preowned with 16000km(10000mi).

I think you need to rip it up a bit and stop babying it so much. Rough idle could also be slightly fouled plugs which can happen sometimes on performance cars with colder plugs driven by an owner who doesn't feed a little speed to their ride once in a while... you know what I'm saying?

[CrownSeven]

I noticed that my S4 does this too. The idle is rock steady, but I can feel shaking in the seat and shifter when I am sitting at a light.

Mine does this as well. Whats interesting is you dont feel the vibrations as much in the passenger seat. Wonder if it has anything to do with the motor mounts. Local stearlership also thought the idle was a bit rough but everything checked out on their end for what thats worth.

[Ketzer7]

I noticed that my S4 does this too. The idle is rock steady, but I can feel shaking in the seat and shifter when I am sitting at a light.

This for me too. The idle can feel pretty rough at times, and I feel it in the seat mainly, but the RPMs never change and remain steady. Noticed this from early on after I first got the car. Thought maybe there was something amiss, but it came back clean after 5K maintenance, and based on this thread it seems normal.

90 degree V6. Will never be as smooth at idle as an I6 or 60 degree V6. Normal.

I can believe this. My old 2001 330Ci was so smooth in comparison, it's part of the reason why I thought there was potentially something wrong with the S4

[FrozenCommunist]

Brand new 2014 S4 here as well with less than 200 km's. I also have a slight rough idle at a stop light. I'm assuming this is normal based in everyone else's response.


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[Triska]

Huh. Didn't even know that. What are the advantages of making the V6 at 90 degrees? Lower center of gravity?

90 degree V6. Will never be as smooth at idle as an I6 or 60 degree V6. Normal.

[Leor604]

In our case it spreads the banks apart and also makes the engine a little lower profile to make room for the supercharger. A good tradeoff in my book.

In the seventies when the Americans first started offering V6 engines, they were literally a 90 degree V8 with two cylinders lopped off. Not ideal but cheaper for them at the time.

[JWreck]

So we're pretty much in consensus that a little shaking during idle is normal?

[MrFunk]

Yes - normal.

[visualguy]

I have the same idle shaking on my S5. Strangely, the SQ5 and A6 (which have the same 3.0T engine) don't have this problem - no shaking on those cars.

[Dr GP]

There is now a TSB for it. (24AS) Involves a ECU reprogram. Had it done 1 month ago. Free out of warranty. I don't notice any difference. http://www.audizine.com/forum/showth...S-2010-2011-S4

[drob23]

I was starting to become concerned about what felt like a rough idle in my car, thinking it might be due to my suspension mods, stg 2 software, exhaust or trans/diff bushing upgrade. Then I sat in a couple brand new 2014/2013 S4/S5's and realized it's like this for all of them. This happened while just sitting in the car coding with VCDS.

[Audi403]

I have this also I think its normal

[Leor604]

There is now a TSB for it. (24AS) Involves a ECU reprogram. Had it done 1 month ago. Free out of warranty. I don't notice any difference. http://www.audizine.com/forum/showth...S-2010-2011-S4

Ditto.

No difference with idle, except they managed to wipe out my VCDS mods when they did the upgrade . Car was all winky, no TPMS, no oil temps, etc, when I got it back from the dealer. Fixed!

[B8_Jim]

In our case it spreads the banks apart and also makes the engine a little lower profile to make room for the supercharger. A good tradeoff in my book.

In the seventies when the Americans first started offering V6 engines, they were literally a 90 degree V8 with two cylinders lopped off. Not ideal but cheaper for them at the time.

The 3.0T block is derived (i.e. used with very slight mods) from the 3.2 V6 which didn't have a SC. I don't know why they used 90 deg, but I believe the SC was fitted to this block after it was designed, so I doubt they picked 90 deg to fit the SC.

[Leor604]

Good point, and a very good question. Why would you choose a difficult-to-balance 90 degree block if it was a "clean sheet" design? Silly Germans!

[RWD2quattro]

my car does the same (2014) but to make things interesting, when I had my 2012 DSG, never noticed it...
I can't remember if my DSG maintained a higher idle or a bit of advanced timing to prevent shaking??

Thoughts?