C6 S6 - a love(hate) story. (long...)

A6 All/ S6 All
#1

Hi guys,

We just got back from a 10-day, 2600Km loop through Croatia, touching every bit of the former Yugo Republic. I have to say that the car is awesome to drive on secondary roads through twisty canyons and coastlines. It’s especially wonderful with the windows down and the exhaust roaring as you punch it to pass slower traffic on a 2- or 1.5-lane road. Even with the stiff suspension, after almost 10 years the chassis is still solid and practically rattle-free.

Unfortunately, we had the windows wide open because the AC (Klimat) compressor died on the 2nd day (http://audirevolution.net/forum/index.php?topic=4122.0), in the mountains about Tirana, Albania. It was 39C that day (~100F) and my wife was furious. I had the freon recharged just before we left on her instructions, so it was doubly “I told you so”. We managed to buy a bucket of ice from a fish market in Montenegro for the next leg, but by this time she was entertaining thoughts of buying “the next car” - and that is not something she ever pays attention to. It won’t happen until after Nov when we find out what country we go to the following year (could be right-hand drive…), but unless I can pull a rabbit out of the hat, my time with the 5.2 may be ticking down.

But despite the lack of AC, I was still driving well on the highway and the twisties and sounded great. It would still idle roughly for a short period during warm up, and I still have an unexplained “clunking” sound from the steering/suspension when reversing or parking, but otherwise it was good. Then with about 250Km to go, and after parking in the hot sun for a 3 hour lunch break in Belgrade) the engine started to run rough and I could tell that the misfires were back. At first it was just a rough idle, but while my wife took a shift on the highway she noticed it was running rough at speed. I scanned it with my Carista OBD and saw the following:

Fault codes:

00797 Sunlight Photo Sensor (G107)
00256 Givers for refrigerant pressure / temperature (G395)
P2179 Bank 2, System too Lean off Idle
P2234 Oxygen (Lambda) Sensor B2 S1, Signal Shorted to Heater Circuit
P2005 Intake Manifold Flap; Bank 2, Stuck Open
P0300 Random/Multiple Cylinder Misfire Detected
P0306 Cylinder 6, Misfire Detected
P0309 Cylinder 9, Misfire Detected
P0304 Cylinder 4, Misfire Detected
00474 Control Module for Immobilizer (J334)
02095 Component Protection Active
I’ll get a detailed VAGCOM scan when I see a mechanic.

I don’t know if it was heat-related or not, but I cleared the fault codes and it ran smoother at speed, but still rough at idle. Then after a 30-min stop at the border (at dusk), it ran a lot smoother during the cooler night temps.

Here’s the State of the Union for the 2.5 years and 24K Km I’ve had the car:

A wonky electrical problem which cause the immobilizer to occasionally “immobilize” the car, or perhaps just not start in cold weather, had me replace

  • battery
  • fuel pump
  • passenger door lock (throwing code to trigger immobilizer?)
  • power relays (2x)
  • oil pan sealing flange, valley pan gasket

Persistent random misfire problems, misfires >4000 RPM, along with oil found in the spark plug tubes ultimately lead me to have the engine removed for a major service (http://audirevolution.net/forum/index.php?topic=3652.0)

  • new coil packs for cyl 6,8,9 (first attempt to fix)
  • spark plug tube seals (x2)
  • replace ® or reseal(L) upper valve gaskets
  • Intake Manifold removed, opened, and inner flap mechanism removed
  • oil separator (torn membrane)
  • breather hose (torn)
  • carbon cleaning
  • resolder T14h wiring harness (heat damage to insulation)
  • fuel injector cleaner G001780M3 (2 times)

While the engine was out, these additional items were replaced as normal or preventative maintenance:

  • valve stem seals (x40)
  • front crank seal
  • water pump, thermostat, & drive shaft
  • engine coolant pipe (x2)
  • coolant temp sensor
  • JHM intake spacers
  • oil pressure switch
  • accessory belt & relay roller

After I got the car back, I thought I was home free! For almost 6 months I was driving with no CEL lights (although the cold weather engine no-start occurred, which seemed to be fixed by new power relays) But lately I’ve been getting misfires on cyl 6,9 again, and now 4. I hope new plugs and packs will fix all of these.

Waiting to be installed…

  • plugs & coil packs (x10)
  • A/C Compressor
  • Orifice Tube, for A/C System
  • A/C Receiver/Drier/Accumulator

Additional outstanding/unsolved issues:

  • steering/suspension clunk when parking/reversing, going to have all the suspension bolts tightened. (http://audirevolution.net/forum/index.php?topic=3450.0)
  • AT transmission PARK switch is wonky, sometimes have to push the shifter firmly to P for it to engage. The key is stuck in the ignition and remote door locking is deactivated when this occurs. But during the HOT weather it refused to engage entirely and I had to lock the doors with the key.
  • misfires on cyl 6,9,4
  • Still need to replace the IM, but waiting to hear if there is an upgraded version coming from JHM

So ultimately, it comes down to this:

  1. have I almost replaced everything that is going to break for the next few years and I should stick with the car (If I can convince my wife to forgive…),
  2. what other (reliable?) AWD car should I consider for my next ride? (Preferably 3-6 yrs depreciated…)
#2

Man, we need to remove some of the hate, in this love/hate relationship. I think its feasible.

Please do 1 if still not want you want we will give you some number 2s, if you provide a budget

I will say it is not necessary, but it’s nice to have a second car when you own a v10, as things can come up. Not as quite often as some other cars assuming the car is straightened out and maintained, but shit happens…

my s6 never left me stranded, and it seems like it didn’t leave you stranded either which is a feat considering the env and trip you were putting it through. I know many other cars might have left you on a tow truck half was through, let’s get this sorted

#3

It’s so weird, I drove the car the morning after to get it washed and it was still a little rough. Then I drove it again in the afternoon and the car was running as smooth as ever after maybe 30 secs or slightly rough idle on warmup. As if nothing ever happened (except the AC is still gone)

I’m about to change the plugs and packs on the drivers side tonight. Pass tomorrow.

#4

Thats an epic story, i think the main problem is easy to fix, next time it happens just put the wife in the trunk, and proceed as intended with windows down, enjoying the v10 sound!

I was in Croatia last summer, it was beautiful, but unfortunately i was stuck in a shitty rental, even though it had aircon the wife still nagged me!

I hope you get it back running 100%

#5

I’ll be in Croatia in a shitty rental myself in a few weeks

#6

It’s awesome - spend as much time as you can in the water, it’s the best. We did a lot of water taxis - Korcula Island and Rovinj were the best, but we sailed by Hvar and it looked like a great place to stop.

#7

Was it running perfect prior to the trip?

What codes if any existed prior to the trip? I am no expert mechanic and some of my questions may or may not help, but most are good things to check anyways if you haven’t looked into it. Would be best if Jimmy or the like from here could comment on issue resolution-

You have done a fair amount of work, its a good and bad thing, as it makes isolating the exact issues a little more challenging. It sounds like the car went through rather interesting climates and differing road conditions. Out of curiosity have you replaced your airfliters, drive through any massive puddles, and also have you checked your MAF connections.

When you installed the Intake manifold spacers did you inspect the actual IM in depth, and the flappers within? It looks like you did, but removed all the flappers? The ECU monitors the flappers, they also serve a purpose and a good purpose so removing them, while removes a a part that might break, also impacts performance and driveabiltiy at times, not always for the better.

Have you examined the injectors and had them flow tested?

Have you checked your cooling system/coolant system, recently? All look good?

This may be overkill (and cause anxiety), but I wonder if it is possible to rig up some key VAG comm parameters into an infotainment system either aftermarket or stock (probably more challenging) to monitor things real-time. T

#8

I was getting a P2005 stick flap before the trip. But the flapper mechanism was completely removed when I did the carbon clean last Dec. So I kinda ignored it. The IM was opened and completely cleaned at the time.

Then I started to get occasional misfires on cyl 6,9. On the last day of the trip cyl 4 was added to the mix.

I just changed the spark plugs and coil packs and now it seems to run smooth at speed, but idle is still rough. The existing coil packs had a Mfg date of 2009. This is what I’m seeing after the new plugs:

EnginePart #: 4F1910552A
Component: 5.2L V10/4V FSI
Coding: 01050009190F0260 (hex)
Fault codes:
P0300 Random/Multiple Cylinder Misfire Detected
P0306 Cylinder 6, Misfire Detected
P0304 Cylinder 4, Misfire Detected
P2005 Intake Manifold Flap; Bank 2, Stuck Open

I have not touched the injectors yet, but injector flow issues don’t come into play at idle, do they?

The air filters were changed a year ago, but they looked OK when I changed the plugs. Not sure about the MAF connections.

Haven’t checked cooling recently, but the temp gauge was rock steady.

And I’m still waiting on the AC parts.

#9

My cylinder 4 is acting up too, though it seems to be the only one. Rough idle during warmup lately too. I haven’t looked into it since my car will be getting a full lookover by JHM in 2 days anyways.

Just curious, for anyone who might know the answer, can we get away with just replacing injectors on only cylinders that need it, or is it a case where when one injector starts to act up, they all should be replaced? With 10 cylinders, that starts to get a bit expensive

#10

Flow test all and replace as needed, but in general you can replace the faulty injectors as needed not all at the same time.

#11

Bank 2 has cylinder 6 in it not sure what could be the cause of cylinder 4. Injector issues can be at any rpm but idle missfires generally lead to vac leaks. It would make sense that the coil packs would be bad if they had a 09 date. So that was a good fix. If you didnt have the missfire before the coil and plug change I would start looking around and see what could be causing the possible vac leak.

#12

One culprit I found during the spark plug change might be the cracked retaining clip on this square connector. It connects to the hose that feeds into the passenger-side throttle-body. Thoughts? Part No?

http://i.imgur.com/Uujb0Lj.jpg

#13

I think a lot of cars have that broken. When I saw that design i saw it was very likely to break. That is a vac line but it still should have the ability to hold onto the neck of the vac attachment point on the intake tube.

Check both the lines and make sure they are fitted properly. It can cause an issue if its not fully plugged in.

#14

I’m still getting really bad misfires on cold start after changing plugs and coil packs. A generic scan shows cyl 4,6 as the culprit - one on each side. The problem seems to settle down after 5-10 mins to a tolerable rough idle.

But I’m wondering if I could have caused an SAI problem when I reconnected the passenger-side air box. Did I miss a connection that could cause SAI problems? I also have a P2005 stuck flap code on the drivers side, and also an IM with the internal flapper removed (since last dec).

I Havent been able to check the fuel injectors because every decent Audi mechanic i know around here is on vacation right now.

#15

UPDATE: ECU heat problems?

My last action was to put in new plugs and coil packs (mid July) but that didn’t fix the misfires. I was getting these codes:

Front passenger’s door
Part #: 4F0910793E
Component: TSG BF
Coding: 51947 (decimal)
Fault codes:
02115 Lock Unit for Central Locking

Engine
Part #: 4F1910552A
Component: 5.2L V10/4V FSI
Coding: 01050009190F0260 (hex)
Fault codes:
P2234 Oxygen (Lambda) Sensor B2 S1, Signal Shorted to Heater Circuit
P1545 Throttle Valve Controller, Malfunction
P1923 Please Check DTC Memory of ECU Number 2

Engine
Part #: 4F1910552A
Component: 5.2L V10/4V FSI
Coding: 01050009190F0260 (hex)
Fault codes:
P0300 Random/Multiple Cylinder Misfire Detected
P0304 Cylinder 4, Misfire Detected
P0309 Cylinder 9, Misfire Detected
P0306 Cylinder 6, Misfire Detected

Infotainment display
Part #: 4F0910732
Component: Interfacebox
Coding: 10003 (decimal)
Fault codes:
00474 Control Module for Immobilizer (J334)
02095 Component Protection Active

My mechanic finally took a preliminary look at the engine today and told me the following:

  • in today’s cooler weather the car ran OK, only misfires on cyl 9. Might be a fuel injector issue.
  • but when he put a heat fun to the ECUs things got a lot worse with bad misfires on cyl 4,8,9
  • he also noticed the vacuum reading was off spec in the intake manifold at idle

He didn’t have time to deal with fuel injectors now, but he suspects that with the misfires, together with my past issues with the immobilizer:

==>. maybe the ECUs are malfunctioning in hot weather?!?? <==

Has anyone ever seen anything like this before? Thoughts?

Additional notes:

  • He told me he’d get the logs tomorrow so I can post them here.
  • last year I tried to fix the front pass door lock with a used Euro version. But I kept getting codes, occasionally the immobilizer would trigger, and the lights never flashed when I locked by remote. Then I put in a new OEM lock from the US and the lights now flash when locked. But I still get codes.
#16

The throught sounds like its possible.

However if you have a S1 02 code that is generally the 02 starting to fail.

The hotter ECU could be part of the issue but that would be hard to tell. You can keep testing and let us know. The ECU does have a roll in driving the coil packs so there is a good chance there is something there

#17

Is the S1 O2 an engine out procedure?

Has anyone exercise tried to use ECUs from an S6 part out?

#18

Someone with more knowledge than myself should start an O2 sensor thread. I have a feeling that as these cars gain some mileage, we’re going to start seeing this happening with more frequency, and when it happens it’s not a small problem. I have “heard” that it requires the engine out to access an O2 sensor, but there might be more than 1 sensor, and if so, they might not all need the engine out to get to them. Someone mentioned, a while back, the possibility of relocating the O2 sensor(s) so that they can be reached easier in the future. It would be great if we could get a tutorial for such an option, if it exists. I think CountVohn and/or V8A6 were looking into it with their new headers.

I also wonder if maybe a new O2 sensor can be installed in a better location, and then simply unplug the old (inaccessible) sensor and plug in the new one, leaving your engine in the whole time. I don’t know what the consequences of leaving an old disconnected O2 sensor would be, but it’s maybe something to think about.

#19

Here is the (transcribed) VAGCOM log after my mechanic checked all the plugs and packs. Apparently I didn’t have a good connection with cyl 1, but he fixed it.

My mechanic just sent me a video, which is here: https://goo.gl/photos/7W3jP4mQKNDZQsKm6

I transcribed the misfires here.

[quote]VAG Number: 4F1 910 552 A

3 Faults Found:

000768 - Random/Multiple Cylinder Misfire detected
P0309 - 001 Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 165003 km
Time Indication: 0
Date: 2016.08.08
Time: 12:19:39

Freeze Frame
RPM: 3057 min
Load: 16.5%
Speed: 0.0 km/h
Temperature: 95.0 C
Temperature: 44.0 C
Absolute: Pres: 950.0 mbar
Voltage: 13.206 V

000772 - Random/Multiple Cylinder Misfire detected
P0304 - 001 Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 165003 km
Time Indication: 0
Date: 2016.08.08
Time: 12:19:39

Freeze Frame
RPM: 3057 min
Load: 16.5%
Speed: 0.0 km/h
Temperature: 95.0 C
Temperature: 44.0 C
Absolute: Pres: 950.0 mbar
Voltage: 13.206 V

000777 - cylinder 9
P0309 - 001 Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 165003 km
Time Indication: 0
Date: 2016.08.08
Time: 12:19:39

Freeze Frame
RPM: 3057 min
Load: 16.5%
Speed: 0.0 km/h
Temperature: 95.0 C
Temperature: 44.0 C
Absolute: Pres: 950.0 mbar
Voltage: 13.206 V

01316 - ABS Control Module
013 - Check DTC Memory - Intermittent
Freeze Frame
Fault Status 00101101
Fault Priority 2
Fault Frequency: 15
Reset counter: 226
Mileage 164845 km
Time Indication: 0
Date: 2016.07.14
Time: 06:52:44
[/quote]

#20

Also, my mechanic noticed a problem with the vacuum pressure in the Intake Manifold (with JHM Spacers Installed, but internal changeover flaps removed).

He put the car in D, drove for a few meters and stopped. then measured about 740-750 mbars vacuum when it should normally be 950 mbar.

Any ideas?