timjerome

Apologies if this is not the correct area to post, but I'm really needing some advise. The engine started misfiring as I accelerated from the on ramp onto the highway and pulled over and had towed to Audi (Downtown Toronto). Here is the report from them:

Nov 17, 2021

DROVE CAR CAR HAS A BAD MISFIRE. SCANNED CAR HAS NUMEROUS FAULT CODES , P164E00 Oil pressure regulation valve electrical error & P030000 Random/Multiple Cylinder Misfire Detected, P33C100 Cylinder 3 Combustion misfire during combined operation detected, P33BF00 Cylinder 1 Combustion misfire during combined operation detected CYLINDER 1 AND 3 MISFIRE.

REMOVED AIR INTAKE HOUSING , SWAPPED COILS OF CYLINDER 1 AND 3 PUT IN CYLINDER 4 AND 6 , AND SWAP SPARK PLUGS LOCATION SPARK PLUGS HAVE FOULED OF THOSE SAME CYLINDER AND PLACED CYLINDER 2 AND 5. REINSTALLED ALL PARTS REMOVED AND PUT BACK IN NORMAL DRIVING CONDITIONS. RECHECKED FOUND CYLINDER ONE HAS A MIS FIRE STILL IN SAME LOCATION REMOVED ALL PLUGS AND COIL , PERFORMED LEAK DOWN AND COMPRESSION TEST IN ALL CYLINDER. COMPRESSION ARE ALL AT 160 PSI CYLINDER OK AND PERFORMED LEAKED DOWN TEST NO LEAKS IN CYLINDERS , NEED TO REMOVE SUPERCHARGER FOR FURTHER INSPECTION

REMOVED UNDER SHIELD, REMOVED, SUPER CHARGER BELT , REMOVED COOLANT HOSES GOING TO SUPER CHARGER , REMOVE SOLENOIDS FOR VACUUM LINES OFF OF SUPER CHARGER , REMOVED SUPER CHARGER . INSPECTED FUEL LINES AND VACUUM LINE FOR ANY LEAKS OR BROKEN LINES. NO BROKEN LINES FOUND. INSPECTED VALVES FOUND NO CARBON BUILD ON VALVES . RECOMMEND TO REPLACE PRIMARY AND SECONDARY FUEL INJECTOR ONE CYLINDER ONE AND ALSO SPARK PLUGS DUE TO PLUGS CONDITION RESULTED FROM FAULTY FUEL INJECTORS

REMOVED FUEL RAIL ON BANK ONE. REPLACED FUEL INJECTORS ON CYLINDER ONE AND REPLACED ALL INJECTOR SEALS ON BANK ONE . REPLACED UPPER INTAKE GASKETS ON BOTH SIDES. INSTALLED NEW SPARK PLUGS AND REINSTALLED ALL REMOVED PARTS IN PREVIOUS LINES ABOVED AND RECHECKED AND CLEAR FAULTS. ALL MISFIRE RELATING FAULTS CLEARED BUT STILL IS FAULT WITH Oil pressure regulation valve electrical error WHICH WAS SUGGESTED BUT GUEST DECLINED , ALL MISFIRE RELATING ISSUES RESOLVED AT THIS TIME



- I picked up the car, all was good for a few days. Low oil notice showed on dash and I put in just under a quart (I did not measure). Drove it for a few more days (drove maybe 300km) and started misfiring again as I accelerated up a hill. Had it towed back and here's the report:

Nov 29, 2021

Duplicated concern vehicle misfiring scanned car found CY1 one and 2 misfiring removed spark plugs found one and two has oil contamination on it. Replaced 2 sparkplugs in cylinder 1 and 2. Took fuel sample, fuel smell strength very weak. check oil level, oil level low with dip stick ring adjuster set to 141. The max level should be at 11. Level was on the 5 mark of measuring tool topped level to correct level, advise guest not to top up engine oil when dash display oil level low, and bring back when need to top up and check by a technician. Current KM reading 1024711KM, we are attempting to track oil consumption to determine the cause of the spark plugs fouling. Parts covered under warrenty.



-I've had the car for just under a week and all seems good. I have been keeping it pretty easy while driving and am a bit afraid to drive too far away from the house. Also, I did not decline to change the oil pressure regulation valve - they txt me when the car was ready to pick up and said that the fault cleared but the CEL may come back on at some point. Oil level after a week still reads full on the dash.

So basically I'm looking for advise. I'm an engineer and pretty techy but certainly not a car guy. Any ideas what could be causing the issue? Could I have put in too much oil and caused the spark plugs to foul? I have scanned with an OBDII scanner and can not see any codes currently.

shum628

I purchased a used 2017 Q7 recently and it is having similar issue, misfiring, spark plug oil fouling, oil pressure regulation valve electrical error and oil consumption. I replaced all spark plugs and coils but the problems still remain at random.
Did your problems fix and how?

09mazda6

from what I've read other potential oil leak/consumption causes on similar 3.0 TFSI in A6 & S4s etc are and in general order of cost/complexity:

• Valve cover gasket,
• PCV failure
• Cam girdle gaskets/sealant could be leaking
• Piston rings
• I'd add that in theory if carbon build up on back in intake valves is too great (bane of all direct injection only engines) that could throw off timing, cause misfires and might also lead to some oil consumption as a side effect.

Pau1004

All,

I know this post is old but just wanted to share what happened to me.

As some of you, I have been having the ame issue with oil consumption and have been adding a quarter of oil every 1000 miles.

Tired of this and Audi saying it’s normal, I took it back to the shop and told them to do a thorough inspection. It turns out that I have pitted cylinders and basically need a new engine. This is causing the oil over usage and also the misfiring.

Audi cannot explain how it happened and Customer Service does not know what to say. In my opinion, an Audi, which is considered to be a luxury car, cannot have an engine lasting 100k miles.

AudiAllTheWay

“Pitted cylinders” causing misfires and oil consumption is caused by long term vehicle storage with moisture and corrosion developing in cylinders, or if a daily driver then caused by one or more fuel injectors stuck open. The ECU cannot detect an injector that is mechanically stuck open usually by physical debris or mechanical needle in seat seal failure so no codes, yet the affected cylinder(s) are flooding 100% of engine run time with fuel injected spray, unburnt fuel washes oil off the cylinder walls causing vertical scratches, wears out piston rings, adds fuel to the engine oil especially during cold start ECU warm up phase aka “dumping fuel” to warm up engine quickly for reduced emissions, greatly accelerates internal deterioration of entire PCV system by being forced to process high volume of VOC’s from fuel contaminated crank case oil. Short drives especially in cold climate will cause oil level rise aka “engine is making oil” and short drive check is remove oil cap and oil will smell strongly of fuel and oil cap rubber gasket will be swollen. Can also park overnight then pull all spark plugs and sniff or scope to check for a raw fuel soaked cylinder.

Once a 3.0T aluminum block with metal insert cylinder wall is damaged to the point of low compression, oil consumption, misfires then the block is done and your looking for a replacement engine.

To best effort avoid stuck open injectors, replace high mileage fuel filter and flush fuel line up to the injector rail then reconnect, maintain the PCV system and use a high quality direct injection fuel system cleaner added to a full tank once every oil change. I replaced my 2011 3.0T PCV Oil Separator at 70,000KM’s along with a decarb and other bits while blower was removed.

These issues apply to most DI engines.

BoxcuTTer

My 2017 Q7 3.0 has 99k miles on it. The oil consumption has gotten very bad. (1 qt/400 miles). During a highway trip, the car began to shake at low RPM and act like it had a misfire. Solid CEL light, no EPC light. Pulled over and restarted, but problem persisted. I was able to get to an Autozone to scan it, they detected primary engine misfire cylinder 5, secondary misfires cylinders 2 and 4. They happened to have a coil pack and spark plug in stock, so I replaced the ones in cylinder 5. Wasn't any better. Spark plug looked very sooty, but no oil or fuel detected on the plug. It's in the independent shop now.

They have previously tried to trace the oil consumption issues without success. No visible leaks, compression test passed, leak down test passed, no visible smoke. Hoping plugs and coil packs fix the issue but I'm thinking it may be the worst case scenario.

AudiAllTheWay

Since your compression and leak down tests are OK then next question has the Oil Separator / PCV assembly been replaced? Don’t use a cheap aftermarket part as the function of the oil separator is critical to long term engine operation. This part is considered a wear item and does not last forever so consider to replace every 60K Miles / 100K KMs for reliability along with a decarb.

Next question has a decarb of the intake ports been done? The carbon buildup can become so excessive that it reduces power and fuel economy and worst case misfires by disturbing the designed swirl effect of the incoming air into the combustion chamber.

Example of an intake port with excessive carbon accumulation. Decarb process is considered a Maintenance Item for direct injected engines. This pic is at 60,000 Miles.


The Oil Separator / PCV underneath the Supercharger is a critical part and suggest replacement every 60K Miles / 100K KM’s for reliability. In addition to clogging air passages the internal rubber diaphragm can tear creating issues including increase the rate of intake valve carbon accumulation.

BoxcuTTer

Welp. The indy shop changed out spark plugs. All had significant carbon buildup. Cylinder 5 had zero compression. They examined it with the scope and there is a hole in the cylinder wall. The piston is completely worn away. They said there is something that looks like white mold in the cylinder.

They're speaking with Audi, but I suspect Audi isn't going to help me as I relied on the indy shop to perform the tests when I complained about excessive oil consumption. The indy shop says that because the leakdown and compression tests were good before, there was no way to predict this would happen.

Car was under Audi Care with the prior owner, but Audi states they can't find any service records at all, which makes no sense. I have owned seven Audis. This will be my last. The car didn't even last 100k miles. I wonder if prior owner knew it had issues and they unloaded it on me. It's been driven about 11k miles each year for two years. Just had to order a replacement headlamp assembly for the bogus running light error message on the LCD too.

Thanks for your input, Audialltheway. I'm not sure if a decarb or replacement of the PCV was done. I can look into it, (not that it does me much good now).

kelisko

I know what you feel. The same thing happened to me. The mechanic informed me that the piston in cylinder 6 has a hole in it and the cylinder head cracked. This happened because I only floored the car to pass another vehicle at high speed. The car was consuming excessive amounts of oil before this happened. It turned out all cylinders compression level are below spec.
Engine: 3.0 TFSI CREC
When new spec: 160 - 200 psi
Wear limit spec: 145 psi
My cylinders, 1-6 (psi): 105, 110, 115, 115, 110, 0
Details here: Beware of oil consumption
This is what I decided to do: Selling my Audis for cheap and leaving the brand
I am adding this thread to the list of threads discussing this issue in my main thread.

BoxcuTTer

Did AoA step up at all? Because I'm being told it'll be about $23,000 to get a new engine in this thing, which is probably what the car is worth.