Horrible idle rattle, I am an idiot

[Juzam]

I am very sorry to post this here since my car is a D4 A8 but I thought I'd get more response since S4 enthusiasts are more active and better informed on tuning.

So today I flashed a very popular stage 2 file from a well respected company and I took off for a drive. I had a custom tune before that so I wasn't expecting this much of a difference. The car went from yeah it's fast to damn that's scary :) I was very happy with it. I tried to test the advanced launch control features but none of them seemed to work. So I revved the car at neutral. The redline apparently went from 4k to 7.5k rpm. I liked it. And like a complete and utter idiot, I revved it again. And again. Then put it in drive and floored it. Immediately the EPC light came on and the car started misfiring. I pulled away and shut down the engine. Started it again and EPC light was gone and the car was fine again, or so I thought.

I noticed a weird noise as I was pulling on my driveway and when I stopped, I could hear an ungodly rattle. I hooked up VCDS and it gave me cylinder 6 misfire and deactivation codes. Right now the car rattles like crazy at idle but seems to stop doing that when I push the throttle a little.

Here is the video:
https://www.youtube.com/watch?v=6OcjeF72YOc

Also, there's an oil leak somewhere :(

I bought this car 5 years ago and it has been rattling each cold start. The chain tensioner is faulty.
I'm thinking it must be the chain and/or tensioner. It must have finally given up. And the oil should be coming from the tensioner cover or ruptured crankcase seals? I couldn't have broken a piston or something right? Oh god I am so depressed right now.

[djn876]

It kind of goes away when revving, which i wouldn't think it would do for a bearing or something like that. Did you pull the plug for cylinder 6?

That does sound terrible though and doesn't sound like timing chains, hard to tell though. Where is the noise really coming from?

You also don't have advanced launch control because you have a zf trans.

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[Juzam]

I have no idea where it's coming from. The car is not vibrating like it's a misfire. And it still pulls great. That's why I thought it must be the chain. But you're right it doesn't sound like the chain.

[Juzam]

Today we listened the car. Removed the supercharger belt and still noisy. First it seemed that the AC compressor was making the noise. Turned off the AC and it got better. The car still pulls exceptionally well but throws off a misfire when pushed hard. So we thought the alternator is fritz. But completely removing the accessory belt this time the noise was still there, albeit much lower. It's definitely coming from the engine. I don't want the dealer to make love to me sensually so we decided that we will solve the issue by ourselves, learning as we go. My mechanic is almost sure that it's the chain and tensioner. No one around has even heard of this engine so it's going to take a lot of work. We are going to start in September. Until then I will be driving my B7.

[Juzam]

I've changed my mind. I'm going to be driving this car for at least 6 more years and I want it to be absolutely spotless proper made. Today I reverted the tune to stock and I will be installing the stock crank pulley as well. Then it's off to the dealer. I've no idea how much they're going to rob me. Fingers crossed. I WILL update this thread unlike so many others.

[Juzam]

UPDATE. Today while taking the car to my mechanic, we took the car to numerous other Audi, VW and Bentley mechanics he is acquainted with, just to get opinions. All of them have listened the car and in unison, they suspect the flywheel. I have no idea the ZF8 actually has a flywheel or not and we could just take the transmission out without the engine. I'm researching this now.

[hunter_killer]

ZF has a torque converter and a flex plate not a flywheel. A cracked flex plate can cause the vibrations and possible misfire if severe enough.


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[Juzam]

Yes that's what I've found. Apparently a new torque converter costs around 1300 EUR. However I am still not sure so I'm taking the car to the dealer on Monday.

[hunter_killer]

I’m not sure how mechanically inclined you are and I’m not sure if your ZF was quite the same as my Ram’s ZF but there should be a dust shield on the front side of the transmission to access the flex plate bolts. You should be able to remove that and either see the flex plate and or use a mirror to see behind that flexplate to look it over yourself.


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[djn876]

Should be pretty much the exact same trans as above, and it also sounds like those other shops don't know what they are talking about.

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[Juzam]

Update today: Dealer is removing the transmission because they're sure it's the flexplate. Will also get a quote on timing chain/guide replacement.

[Quattro_Gang]

Update today: Dealer is removing the transmission because they're sure it's the flexplate. Will also get a quote on timing chain/guide replacement.

That is going to break the bank

[wrxkyle]

Update today: Dealer is removing the transmission because they're sure it's the flexplate. Will also get a quote on timing chain/guide replacement.

timing chain labor is more than swapping engines labor as they have to pull the motor, then do the timing chain, so hopefully it's not that. i'd sell the car to carmax before going that route...

[hardfive]

Warranty company - Has the car been tuned?
You - * Internal monologue "Like a piano?" Absolutely not.
You - Prays in finance

[Juzam]

You guys do realize that I'm living in Turkey right? Cars are ultra expensive here and labor is dirt cheap. The dealer quote for the transmission mount/demount labor is 590 us dollars (half that when using my mechanic). On top of that, the economy completely shat itself during the last 2 years and that means everything has tripled the price. My car, which I bought for 90.000 EUR back in 2015 now costs, if I sold it today, as is, 95.000 US dollars. A brand new 2021 A8 with a 3 liter diesel engine goes for 400.000 us dollars. So no, thank you, I will be driving this car until it literally falls apart.

[simonh]

I had a lose flex plate that rattled at idle and went away with revs. I assumed the DMF was broken so bought a new one and clutch. It was fixed with some loctite and torqued to spec, hasn't come back since.

[Juzam]

UPDATE:

They've told me that the flexplate and housing bolts came loose and broke off, damaging the flexplate. They've asked me if I'd taken off the transmission myself. I of course said no.



Video translation:
-(Has) this bolt been broken recently ?
-Yes it's broke off recently.

-Bolts.... again. Is this what's making the noise?
-Yes this is making the noise.
-OK
-The bolts are loose, they've not been tightened properly.

Well actually, back in 2016, the previous owner of my car got the dealer at Istanbul to replace the transmission out of warranty. So it turns out THE DEALER is the idiot, not me. I will be telling the guys at Ankara to replace it free of charge. If they won't, then I will be paying for it and suing the pants off of Istanbul. Cheers.

PS: They also found that the oil leak is caused by the drain plug.

[hunter_killer]

Nice good luck! The ball is in your court then! Let us know what happens with the warranty work.


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[RoofRails]

UPDATE:

They've told me that the flexplate and housing bolts came loose and broke off, damaging the flexplate. They've asked me if I'd taken off the transmission myself. I of course said no.



Video translation:
-(Has) this bolt been broken recently ?
-Yes it's broke off recently.

-Bolts.... again. Is this what's making the noise?
-Yes this is making the noise.
-OK
-The bolts are loose, they've not been tightened properly.

Well actually, back in 2016, the previous owner of my car got the dealer at Istanbul to replace the transmission out of warranty. So it turns out THE DEALER is the idiot, not me. I will be telling the guys at Ankara to replace it free of charge. If they won't, then I will be paying for it and suing the pants off of Istanbul. Cheers.

PS: They also found that the oil leak is caused by the drain plug.

Wow I'm glad they found the issue for you. Appreciate the updates !

[Juzam]

Welp. Not so lucky apparently since they're also changing the torque converter. The invoice is here:
Screenshot 2021-08-11 012846.jpg
All prices are in Turkish Liras.

I will try my best to protest, but I doubt they'll lower it further than 3000 US Dollars. And since the previous work has been done 5 years ago, my lawyer doesn't think anything will come up. Ah well, at least now I KNOW this car won't be a problem for me in the future.

And the total labor is like I've said, less than 300 dollars. The rest is parts.

[simonh]

That was exactly the issue I had on my 2011 S4 except I was lucky enough not to break any bolts. 100% for certain my transmission had never been off so it looks like the bolts just came lose on their own.

[blackfunk]

Might be cheaper to ship my car to Turkey have work done then have it shipped back to the states. LOL.