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Discussion Starter · #1 ·
Hi guys,

I have an Audi S5 4.2L V8 that isn't far away from being set on fire...

It's developed a misfire that's worse when it's cold, until it gets warm - then after a long drive it is worse again.

Feel it slightly at idle but up until 2.5/3k RPM it's fine, then it starts kicking in worse and triggers the EPC light.

So far, I have changed the following:
8 x new spark plugs
8 x new coil packs
4 x new coil pack connectors (as they were snapped)

It's got slightly better, but still not there!

It's brought up the following codes, after I changed Spark Plugs & Coil Packs when it was still misfiring

P130A - 001 - Cylinder Disabling
P0087 - 008 - Fuel Rail/System Pressure Too Low (this hardly comes up, think it's come up twice in the space of a few months)
P1367 - 004 - Cylinder 5 Ignition Circuit - Open Circuit
P0305 - 001 - Misfire Detected Cylinder 5
P2316 - 001 - Control Circuit for Ignition Coil 6 - Short To Plus
P0306 - 001 - Misfire Detected Cylinder 6

I also had the following codes come up once, which I am guessing is due to the misfire:
P0421 - Warm Up Catalyst Efficiency Below Threshold Bank 1
P0431 - Warm Up Catalyst Efficiency Below Threshold Bank 2

I changed the Coil Pack connectors on 5 & 6 as they were completely knackered and thought that might've been it...

And since, it is still doing the same thing (maybe slight improvement), but now brings up

P0302 - Cylinder 2 Misfire Detected when the EPC light comes up
And has also shown P0087 Fuel Rail/System Pressure Too Low code once again (but not come on since).

Any ideas what this could potentially be? Rocker Cover gasket is leaking slightly, but spark plugs didn't make a difference at all.
 

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I've had similar issues with my 2010 for different codes but misfire related.

Just to know, was any carbon cleaning ever performed on this vehicle? Total miles on vehicle?

I don't have any good answers for you either but I will relay what is done to mine at least as a comparison. Next thing we are doing is a leakdown/compression test and changing a fuel filter. Mine has 79k miles and had carbon cleaning done twice during my ownership (which started at 3k). The FSI system along with our crappy ethanol gasoline helps contribute to all of this misery.
 

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Run some STP or similar additive thro the fuel system to clear out the remaining crap????
 

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Run some STP or similar additive thro the fuel system to clear out the remaining crap????
It is more involved than using those types of products. When carbon build up occurs, it takes removal of the manifold intake and physical work to clean out the deposits - many threads on here will illustrate.
In short, the fuel treatments cannot get to it. An inherently flawed issue caused by the FSI design.
 

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Discussion Starter · #7 ·
I've had similar issues with my 2010 for different codes but misfire related.

Just to know, was any carbon cleaning ever performed on this vehicle? Total miles on vehicle?

I don't have any good answers for you either but I will relay what is done to mine at least as a comparison. Next thing we are doing is a leakdown/compression test and changing a fuel filter. Mine has 79k miles and had carbon cleaning done twice during my ownership (which started at 3k). The FSI system along with our crappy ethanol gasoline helps contribute to all of this misery.
It's just hit 139,000 miles.

There is an invoice for a Carbon Clean this year when I bought the car, wasn't done in my ownership. However, there is also an invoice for cambelt & water pump gaskets (even though they're chain driven...!) so not 100% sure it's been done.

Think this is my next step to try a carbon clean.
 

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Does sound like carbon if you have changed the plugs and coil packs.

HP Fuel pumps are also known to give poor running on these V8s.

Next steps would be compressions in cylinder checks (if low, can be sticky or carboned up valve stems/seats) This will cause lumpy running. Also piston rings/bores can give rough running is worn or damaged.

Does it emit blue smoke?

As said, there are all sorts of 'Carbon cleans'. How much was the carbon clean that was done?
 
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Not to derail the original questions here but I am sadly faced with an unexpected disposal of my 2010 S5. The mechanic has discovered all kinds of oil in the spark plug tubes (when he was about to do the compression and leakdown test). He concludes the camshaft caps are the culprit of these leaks. The car has 79k miles on it, was properly (over) maintained. A carbon cleanout done twice and now this.
Says engine must be removed so another 5/6k USD on top of 3k just spent about 6 months ago for all kinds of work related to other misfires. Main issue was misfire was not consistent on most examinations of his or mine (I have VAG COM so i was keeping track too).

Needless to say, I am rather livid this car now leaves me with no choice but to dump it instead of spending what will be equal to or close to the value of it with uncertainty on future issues. Age caught up with it I guess but I honestly thought it would see 130k or more miles (with obvious maintenance needs) before I would finally say I'm done.
 

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Oil in the plug tubes is normally the rocker cover seals. Can be done without removing engine and certainly not a 5-6K job!

Good proper oil, not sure what your mechanic uses and every 5-6k miles should keep oil seals leak free. I had a car renowned for oil leaks, but using Mobil 1 every 3k miles and nipping up the cam covers gave me a leak free engine.

I presume your mechanic means camshaft cover/rocker cover and not caps? Caps are the 'bearing' clamps that hold the camshaft so not sure how oil would get into the plug holes if they are bad as they are internal.

I'd say new mechanic who knows what they are doing before writing off your S5! :)
 

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I may be getting the cam description wrong but was definitely oil in the plug tubes/gaskets from pics sent. Then a burnt plug.

Not a fan of Mobil 1 but I can say quality oil products have been used the entire life of this car since I owned it.

May see about second opinion but this particular indy has been reliable for many cars for multiple years. Would hope if it were something that simple (rocker cover seals), that would be easily discernible along the way
 

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When I was using Mobil 1, it was about 25 years ago, so not as much fully synth oil back then. :) I use Castrol Edge now.

Yeah, if you look in the plug tubes, there is only 1 seal, the cam/rocker cover seal near the top. Oil can't get into it any other way.

Was the burnt plug on the ceramic or the tip that is in the cylinder?
 

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Dave I too use Castrol Edge and find it excellent. I ran my old A5 from 100k to 200k kms and now my S4 is on 220k kms and still drives great with no oil consumption. High miles on these cars are I think NOT a major issue as long as the car gets regular oil and fiter changes.
 

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Small update.

After retrieving the car, the explanation was the gasket involved is sandwiched in the middle of the block more/less. The term was more of a "cam girdle" if you will. It has dried over time and to replace, the cam covers on the back of the engine (and presumably cams themselves) are part of the equation as this section is up against the firewall. Engine removal (according to mechanic) required to get to these for removal. The valve cover gaskets were not a culprit in this instance and the tubes are collecting oil seeping through this middle gasket.

For a car 13 years old and regularly driven with proper maintenance, it is absurd to me this failed but the design (flaw?) may be a factor here on what may otherwise be a simple job on say the 2.0 or another engine in the VAG family
 

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if you look in the plug tubes, there is only 1 seal, the cam/rocker cover seal near the top. Oil can't get into it any other way.
Sorry, but this is so wrong I couldn't help myself not replying now, hopefully once and for all.
I hear this quite often on forums, not sure where people are getting this info from :rolleyes: :rolleyes:

You got 2 seals down there:
No3
Rectangle Font Engineering Parallel Slope

Part Nr. 079103483T & 079103484C



No10
Font Line Parallel Slope Engineering

Part Nr. 079103650C & 079103649C


First one is the easy and cheap to replace, where lower one (under cam retaining frame) is whole different story. Ask me how I know 😁 (oh, and yes, I have fixed this leak, and no, I did not remove engine nor any valve gear related item)
 

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@keram - No need to get contentious, I am merely the messenger here.

If you have something positive and helpful on details of how you fixed the lower one, please feel free to share as I will likely have a dealer finally take a look as I have contacts there for cars still under warranty.
 

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I think the post was correcting me Tony :)

Apologies, I had forgotten about the cam cradle :) But still doesn't warrant engine removal, just have to unbolt a bit further down. :)

I did think about the V8, but went for the 3.0T. I drove a friends V8 manual, sounded really nice!
 

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I think the post was correcting me Tony :)

Apologies, I had forgotten about the cam cradle :) But still doesn't warrant engine removal, just have to unbolt a bit further down. :)

I did think about the V8, but went for the 3.0T. I drove a friends V8 manual, sounded really nice!
No problem. I just realized I didn't mention V8 on mine but was in the thread about the V8. My mistake for not making that clear.

In any event, I am going to get at least one other opinion and go from there.

@audis5b8 - any updates on your diagnosis/progress after all my derailing of this thread?
 

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Closing the loop here for me, Audi dealer mechanic affirmed the indy's diagnosis. While it can be done to replace one of the interior gaskets with the motor still in, he knows it is not always easy to line things back up without having the engine out while using mirrors to keep all things straight - some of the tolerances are truly tight. If there is not someone local to me that could do this and guarantee it would work, I am not pursuing (and this car is a daily driver). While I appreciate some believe it can be done with the motor in, I am not taking chances.

I can't justify the cost or the risk of finding other problems (13 year old gaskets/hoses/plastic pieces) by pulling the engine out. Sadly, I have to let this one go. With 79k miles, it can be someone's project. Dealer tech also agreed with indy mechanic this was not the best way to design the motor with this gasket so hard to replace.
 
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