C6 S6 Engine Issues... Help.

A6 All/ S6 All
#1

Hi all,

First time poster here, but long time reader. About a year ago I bought a 2007 S6 one owner car with 37k miles (with a 5 yr / 50k JDMA/Fidelity Platinum Warranty). I immediately did a service and had it inspected (high level) and since then I’ve put about 3500 miles on it. A couple of months ago I had a check engine light come on and the anxiety started. The initial diagnosis was that there was an intake flap/manifold issue (the flap was stuck). While the car was in the shop I had the oil changed, air filters replaced, spark plugs replaced, and while the manifold was off I went ahead and had a carbon cleaning done as well. It wasn’t terrible, but knowing what can happen I did it pro-actively. I get the car back, carbon cleaned, new manifold and new check engine light… Every time one thing is fixed/changed, the light comes back… It’s now been about 6 weeks and below is a list of what’s been done (and shop notes/invoices are attached).

Entire manifold replaced
Checked for vacuum leaks and replaced a hose with a very slight crack
Carbon Cleaned (walnut blasted)
New spark plugs
New Coil Packs on cyl 5-10
New PCV (Crankcase Valve)
New Fuel Injectors on cyl 5-10

The misfire’s have come on cylinders 5-10, not sure about the latest yet since it happened on Saturday and the “engine specialist” at the dealer who’s been working on my car was out. The injectors were the last thing replaced. About 10-15 minutes after picking up the car under moderate acceleration (about 4000 RPM) I felt a little stutter/misfire, and the Engine Light started flashing again. Upon easing off the accelerator the light went off. I turned around and headed back to the dealership. I again tried a heavy acceleration run, light started flashing and back it goes to the dealership. So far the warranty company is in for about 8-10k, but more importantly, I’ve been dealing with this for about 6 weeks. Anyone any good pointers here? I know I’m not the first with these issues, but I also feel like we’ve hit the most common problems and I fear there’s no end in sight. Any help/insight is much appreciated…

End rant.

#2

Pictures won’t post, so including dropbox link below.

https://www.dropbox.com/sh/zu26vds6occo4vz/AAC7Kn_y81mkmXuP1vFBwjOTa?dl=0

#3

Welcome to the site. Your in the right place. The idea of AR is to get all the technical guys in one spot and make sure people are getting real answers to real concerns. All at the same time gettting lots of useful feedback without tons of ranndom trolls telling you to go buy another car.

To start if you want to post picrures use this

http://audirevolution.net/image_uploader.php

From what I have and others have seen the V10 cars are great fun but you really need to be ontop of looking for the small detials and signs.

a few questions. Do you have a vag com. Where are you located and is the car at a dealer or just an indy shop.

The postive side of this is the warranty seems to be footing the bill for the technitions tring to find the cause of this.

The intake manifold is a big issue and the flaps on the inside to break. In stalling the intake might not have been enough they might need to go back in and re tq down the intake.

Adding the plugs and injectors will help and should be done anyway. The injectors are a common failure and if they did actually replace the injectors that is one good thing to have on the list.

Have you gotten any of these replaced parts back. Just to make sure they have in deed been replaced.

If the missfires are exclusivly on one side and the missfire is on all the cylinders the next things to look at would be as follows

First check the intake for leaks at the head. That is the first big issue. A smoke test can be very helpful as most of the intake manifolds the dealership gives out are reman units. Some of them have leaks and should be tested.

Due to the entire bank 2 having missfires its a good idea to look at the HPFP unit on the bank 2 side. It isnt super regular that they fail but they do fail. Given all the other parts you changed that would be the one big thing that stands out.

I would look in that direction before moving on.

If you have questions always post them. No question is a bad quesion. We are all here to help

#4

Welcome. Most of the things you have replaced are pretty common problem areas. Even if they are the culprit of your current code they will cause problems in the future so it’s good that they are taken care of. As justincredible mentioned get a vagcom and post exact symptoms and codes here. I found the c6 s6 pretty reliable once you handle the known gremlins, odds are you are dealing with a small issue…that is hopefully resolved soon. Btw, you have a pretty low mileage beast, post up pics!

#5

OP, I apologize in advance since I don’t have NEARLY as much technical knowledge as many others in this forum, but I will say that from the trends I’ve noticed, most of the “major” issues with these cars seem to happen before about 40k miles. So hopefully that helps you sleep better - that once you get all the “kinks” worked out, you should be in good shape for a very, very long time.

I bought my '07 S6, sight-unseen, with no warranty and 90k miles, and was VERY nervous about catastrophic failure. My nervousness was furthered by a complete loss of throttle response over 3k RPM and a bunch of CEL’s after only 10k miles. In my case (and I realize this isn’t the same problem you are having), it was resolved with $700 in parts that I installed myself in about 30 minutes, and it’s been good to go for the last 15k miles. These engines are really quite bulletproof. Other parts may fail, but your block should be good for a very, very long time as long as you take care of it.

Anyways, sorry I have nothing useful to add, was just hoping to calm your nerves a little!

#6

Hey Guys,

Thanks for the quick feedback and words of comfort. I’m in Atlanta. I’ll remain hopeful that this is just a speed bump, it’s just crazy to me that a car with such low mileage can have so many issues (and definitely glad I got the warranty). I don’t have a vag com, but have seen it mentioned a lot. Since it’s basically been in the shop the last month, I figured I’d wait until I got it back before buying one.

I first took the car to an indie shop, and after getting it back and taking it back in a couple of times, I took it to the dealer (actually they did for me, they have been awesome despite this being frustrating for everyone) and the dealer has their “engine specialist” working on it. I think one of them tried swapping fuel pumps from side to side to see if it caused/transferred the issue, but I’ll suggest they go back and check it again and will also have them check the intake manifold for leaks. I’ve asked for the diagnostic info as well and will post here when I get it back.

Thanks for the support (technical and moral).

#7

Quick update… Misfire on cylinder 2. Bad fuel injector. Shooting for replacing the entire bank and hopefully we’ll be done…

#8

Good luck man. In the future, make sure that you get the fault codes that are stored whenever the check engine light comes on. That would be drastically more helpful for us giving advice on how to proceed. That is where a vagcom would come in really handy.

I am starting to think that all the 4.2 and 5.2 FSI engines really need to replace the PCV valve and get all of the fuel injectors rebuilt/flow matched whenever they do a carbon clean.

#9

That’s probably a good idea jimmy…I honestly hadn’t heard of the pcv valve needing to be replaced with any frequency until I started hearing about it on the forum. Sounds like the right thing to do tho.

#10

It seems these big V10 cars like to eat injectors. It might make sense to change all of them. at one point it seems there was a bad injector on the other side.

Like jimmy said you should try to get a vag com so you can capture the codes and post them here. It would probably have helped us in getting you more data to help support you. If your warranty runs out JimmyBones is a great resource close to you. He is an ex audi tech that reallys helps work on and fix a lot of audi cars.

#11

Each time we go through one injector they wind up covering about 6 hours of labor + injector costs. I’m hoping the warranty company will just replace all of them (the remaining 4). They’re coming out again and will hopefully green light it.

Where’s the best place to get a vag com? Also @jimmybones where are you? Would love to connect sometime (feel free to DM).

#12

You can buy from rosstech directly for the vagcom

#13

you can get it here… Lots of good data and info to look over

http://www.ross-tech.com/products.php

#14

Ok, injectors on cylinder 1-5 and all gaskets are being replaced under warranty… They had to order some parts, so it looks like I’ll have it back Monday. Hopefully this will be the end of the Check Engine Light issues. Thanks everyone!

#15

I cant see it still having issues after changing all those parts. You have replaced all the parts that seem to fail

#16

That’s positive news (finally). What can I do to get and ensure its a long time before I have to go through this again? I’ve heard octane booster, drive it hard regularly, carbon blasting regularly (how often)? Any other ideas suggestions? If prefer an ounce of prevention vs a pound of cure. This has been such s pain in the ass…

#17

I think you said you already had the JHM intake spacers. Spacers help reduce the intake temps by a big margin. doing so helps keep carbon away longer. It helps keep the intake trac temps more in check while giving the car a nice boost in power on the hotter days.

With the new injectors you want to make sure to use a good grade of gas. Also make sure to change your fuel filter. Dont over fill your oil as that can get into the intake track and then into the cylinders.

Those are just a few steps

#18

I don’t have the spacers, but I’m afraid installing them would void my warranty. On the gas front, is it more than just octane (I always use 93), but I have access to 98 or higher race gas. Is it a good/bad/neither idea to run on that from time to time or to use it as a mixture with normal premium gas? I assume it would be better to use a few gallons on a near empty tank as opposed to mixing 50/50 on a full tank?

#19

I dont see spacers as something that would be a warranty concern. So it might make sense to consider them. Your not really removeing and replacing a part so much as your adding to an exsisting part. Much like wheel spacers are just adding to the current configuration

On the gas. That can be hard if the better fuel is something that the fuel is used regularrly and its not a siuation where not a lot of people use that pump then you dont want to use that pump. I dont know if that made sense but if you use gas from a gas station that dosent get a lot of traffic the fuel in the containment units can gather water and water will quickly kill your injectors.

It might be a good idea to use injector cleaner ever few fill ups.