S7 (C7.5) Cylinder Misfires & More

[RAF_S7]

Hey Guys,

So Ive had two scares with the S7 over the past month, both of which have resulted in reduced engine power, very obvious misfires, EPL warning light, and notice to stop ASAP and turn off the engine. Not easy when your on the outside lane of the freeway and traveling at 75MPH

Anyway, managed to get home today in Limp-Home mode and run some diagnostics, as shown below.

Will take to dealer tomorrow and see if they can run some diagnostics. Im not tuned, but have done the exhaust modifications, so should be an interesting conversation!

==================================================

10203 - Random/Multiple Cylinder Misfire Detected
P0300 00 [039] - -
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 32996 km
Date: 2017.03.06
Time: 17:47:16

Engine speed: 3186.00 /min
Normed load value: 13.3 %
Vehicle speed: 95 km/h
Coolant temperature: 95 ∞C
Intake air temperature: 32 ∞C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 12.651 V
Unlearning counter according OBD: 80
Engine status: COENG_RUNNING
Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

10593 - Cylinder 3
P0303 00 [039] - Misfire Detected
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 32996 km
Date: 2017.03.06
Time: 17:47:16

Engine speed: 3186.00 /min
Normed load value: 13.3 %
Vehicle speed: 95 km/h
Coolant temperature: 95 ∞C
Intake air temperature: 32 ∞C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 12.651 V
Unlearning counter according OBD: 80
Engine status: COENG_RUNNING
Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

10205 - Cylinder Disabling
P130A 00 [167] - -
MIL ON - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 32996 km
Date: 2017.03.06
Time: 17:47:30

Engine speed: 3346.00 /min
Normed load value: 17.6 %
Vehicle speed: 99 km/h
Coolant temperature: 95 ∞C
Intake air temperature: 30 ∞C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 12.816 V
Unlearning counter according OBD: 40
Engine status: COENG_RUNNING
Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

Readiness: 0000 0000

========================================
Address 03: ABS Brakes (J104) Labels: Redir Fail!
Part No SW: 4G0 907 379 S HW: 4G0 907 379 S
Component: ESP9 Premium H01 0530
Revision: -------- Serial number: --------------
Coding: 65B6DE4BA66D7BD29B00
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_ESP9BOSCHAU57X 004018
ROD: EV_ESP9BOSCHAU57X_VW51.rod
VCID: 418F29A4D09DC049AD-8014

1 Fault Found:
36352 - Function Restricted due to Insufficient Voltage
U1400 00 [040] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Mileage: 32397 km
Date: 2017.02.26
Time: 13:07:46

VzRef: 00
Bit Info 1: 40
Bit Info 2: 0F
Bit Info 3: 22
Bit Info 4: 1F
Uz: 6B
Unlearning counter according OBD: 12

============================================

Address 13: Auto Dist. Reg (J428) Labels: 4H0-907-561.clb
Part No SW: 4G0 907 561 B HW: 4G0 907 561
Component: ACC3 H21 0053
Serial number: 00000000000000
Coding: 7E04010101
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_AdaptCruisContrAU57X 002014
ROD: EV_AdaptCruisContrAU57X_002.rod
VCID: 295F910448ED280995-807C

2 Faults Found:
105472 - Function Restriction due to Faults in Other Modules
U1113 00 [008] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Reset counter: 2
Mileage: 32397 km
Date: 2017.02.26
Time: 13:07:47

Control Module temperature: 8 ∞C
Voltage terminal 15: 11.531 V
Velocity_vehicle_reference: -0.01 m/s
Longitudinal_acceleration_vehicle_reference: 0.00 m/s≤

140288 - Function Restriction due to Faults in Other Modules
U1113 00 [008] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Reset counter: 2
Mileage: 32397 km
Date: 2017.02.26
Time: 13:07:48

Control Module temperature: 8 ∞C
Voltage terminal 15: 13.640 V
Velocity_vehicle_reference: -0.01 m/s
Longitudinal_acceleration_vehicle_reference: 0.00 m/s≤

================================================== ===

Address 19: CAN Gateway (J533) Labels: None
Part No SW: 4G8 907 468 F HW: 4G8 907 468
Component: J533--Gateway H14 0083
Revision: -------- Serial number: 00000001943179
Coding: C0ED07481C
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_GatewPkoUDS 001028
ROD: EV_GatewPKOUDS_VW51.rod
VCID: 3B735B4CB271AA99F7-806E

Battery Monitoring Control Module:
Subsystem 1 - Part No SW: 8T0 915 181 HW: 8T0 915 181
Component: J367-BDMHella H03 8041
Serial number: 2951487403

Voltage stabilizer:

2 Faults Found:
12290 - Quiescent Current
U1406 00 [008] - Too High
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 7
Fault Frequency: 77
Reset counter: 25
Mileage: 31086 km
Date: 2017.02.07
Time: 17:10:32

Voltage terminal 30: 12.2 V
Voltage terminal 15: 0.0 V
Control Module temperature: 22 ∞C
System status: LIN_active
IN ESP_standstill flag: no standstill detected
Engine running: OFF
IN ZAS_Te_X: OFF
Terminal 15 status via CAN: OFF
Terminal 15 status: OFF
Datenfeld: 0

12291 - Energy Management Active
U140B 00 [008] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 7
Fault Frequency: 29
Reset counter: 23
Mileage: 31128 km
Date: 2017.02.08
Time: 01:18:10

Voltage terminal 30: 12.1 V
Voltage terminal 15: 0.0 V
Control Module temperature: 15 ∞C
System status: Awake_Timer_active
IN ESP_standstill flag: no standstill detected
Engine running: OFF
IN ZAS_Te_X: OFF
Terminal 15 status via CAN: OFF
Terminal 15 status: OFF
Datenfeld: 1

===============================================
Address 8B: Adaptive Cruise 2 (J428) Labels: 4H0-907-561.clb
Part No SW: 4G0 907 541 B HW: 4G0 907 541
Component: ACC3 H21 0053
Serial number: 00000000000000
Coding: 7E04010101
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_AdaptCruisContr2AU57X 002012
ROD: EV_AdaptCruisContr2AU57X_002.rod
VCID: 275B973C5EF91E7983-8072

2 Faults Found:
105472 - Function Restriction due to Faults in Other Modules
U1113 00 [008] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Reset counter: 2
Mileage: 32397 km
Date: 2017.02.26
Time: 13:07:47

Control Module temperature: 8 ∞C
Voltage terminal 15: 11.932 V
Velocity_vehicle_reference: -0.00 m/s
Longitudinal_acceleration_vehicle_reference: 0.00 m/s≤

140288 - Function Restriction due to Faults in Other Modules
U1113 00 [008] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Reset counter: 2
Mileage: 32397 km
Date: 2017.02.26
Time: 13:07:47

Control Module temperature: 8 ∞C
Voltage terminal 15: 13.631 V
Velocity_vehicle_reference: -0.00 m/s
Longitudinal_acceleration_vehicle_reference: 0.00 m/s≤


-------------------------------------------------------------------------------
Address 8E: Image Processing (J851) Labels: 4H0-907-107-V2.clb
Part No SW: 4H0 907 107 H HW: 4H0 907 107
Component: BV-SG H33 0090
Serial number: 005000623007157
Coding: 03C23B1A1111
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_BC7 001001
ROD: EV_BC7.rod
VCID: 2C516810471F3D216E-8078

1 Fault Found:
0028 - Function Restriction due to Faults in Other Modules
U1113 00 [008] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Reset counter: 2
Mileage: 32397 km
Date: 2017.02.26
Time: 13:07:47

Outside air temperature: 9.5 ∞C
Voltage terminal 15: 10.8 V
Control Module temperature: 0.0 ∞C

[MadAboutCars]

Interesting. Other than the misfire, those are all of the error codes you get when the air suspension is disabled. Have you adjust the ride height recently? 600km's ago looking at the log.

[RAF_S7]

Interesting. Other than the misfire, those are all of the error codes you get when the air suspension is disabled. Have you adjust the ride height recently? 600km's ago looking at the log.

Suspension is totally OEM, and hasn't been adjusted.

Address 34: Level Control (J197) Labels: 4G0-907-553.clb
Part No SW: 4G0 907 553 G HW: 4G0 907 553 F
Component: LUFE-DAEMPFER H19 0783
Coding: 008002
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_AirSuspe 003025
ROD: EV_AirSuspe_VW51.rod
VCID: 2F6B7F1C760946394B-807A

No fault code found.

[GolfGL]

Based on my experience, the misfire is the main fault here. The other faults are usually a loss of communication between modules due to battery or low voltage.

For my 2013, I had misfires on cruising, engine warm, high load conditions, always random + cyl 3. Interesting you have the same cylinder 3 misfiring in addition to random. Happened stock or tuned. Dealer replaced coil pack on Cyl 3 and I changed out all the spark plugs at 110k as it seemed the previous owner did not change plugs at 55k (mfg date code on removed plugs were prior to build date of car and were extremely fouled up). I put Sea Foam in the gas to clean up the injectors and I got another misfire the next morning. Since then, it has been running perfectly.

Read up on the other thread here about misfires on RS7 cyl 5 in similar circumstances. It seems when engine returns to 8-cyl mode from 4-cyl mode, there is a higher probability of misfire from the new cylinders firing up.

[MadAboutCars]

Okay. Going by the ABS and CAN module it seems to be a battery voltage problem. Something is drawing too much current.

[MadAboutCars]

I'd be tempted to do a clear all DCT's and see if it happens again after the engine relearns (gets to readiness after about 100km). Might be fuel related (bad octane level).

[RAF_S7]

@MadAbout -

Interesting you mention the voltage issue. I had one other fault, which tbh I just assumed was a bulb out I so ignored:

1 Fault Found:
02123 - Door Warning Light / Entry Light
012 - Electrical Fault in Circuit - Intermittent
Freeze Frame:
Fault Status: 00101100
Fault Priority: 3
Fault Frequency: 1
Reset counter: 3
Mileage: 32397 km
Time Indication: 0
Date: 2017.02.26
Time: 13:07:23

Regarding just clearing the DCTs. This is the second occurrence, and both happened on a fast motorway/freeway, which could have had disastrous consequences (complete lack of power, followed by obvious misfire and de-acceleration) If I clear the DCTs the dealer will have nothing to diagnose when he hooks up his diagnostics (unless it reoccurs on the way to the dealer)

[MadAboutCars]

Yeah, I meant clear the DCT's and don't go to the dealer, but I can understand your concern of it happening again. I've had a knock sensor fault twice in the past, but not for a long time now after resetting all DCT's and using different gas.

Interesting that that light warning coincides with the ABS warning, but not with the first CAN bus fault.

[RAF_S7]

I'd be tempted to do a clear all DCT's and see if it happens again after the engine relearns (gets to readiness after about 100km). Might be fuel related (bad octane level).

Yeah, I meant clear the DCT's and don't go to the dealer, but I can understand your concern of it happening again. I've had a knock sensor fault twice in the past, but not for a long time now after resetting all DCT's and using different gas.

Interesting that that light warning coincides with the ABS warning, but not with the first CAN bus fault.

Both of my issues occurred on different tanks of gas - Im running 99RON.

I'll take to the dealer in the morning, see if they can run some diagnostics. Not sure if they will point and scream TD1 as I have a custom exhaust fitted. Guess Ill find out.

Thanks for the feedback

[pez81]

Others said it but first thing that stood out to me was battery issue. Could be shorting I guess. Have you used those milltek plugs yet for the exhaust? If not there's exposed wiring until you do and water can get in them.

Sent from my XT1580 using Tapatalk

[pez81]

When I modded my exhaust the same as you did I had a couple of issue with current. Also another guy on the UK forums with an rs6 had the same issues and I think he had modded his exhaust or water got in the wiring loom. I'd bet it's your battery or exhaust wiring loom.

Sent from my XT1580 using Tapatalk

[RAF_S7]

Others said it but first thing that stood out to me was battery issue. Could be shorting I guess. Have you used those milltek plugs yet for the exhaust? If not there's exposed wiring until you do and water can get in them.

Sent from my XT1580 using Tapatalk

Hey Tom,

Yes there is a Milltek plug on the drivers side, on the PAX side l installed the valve from the original exhaust. I still get occasional flap errors though.

[RAF_S7]

So, Master Tech has done his initial diagnosis and root cause - Misfire in cylinder 3, due (he thinks) to a problem with the spark plug. (Not a warranty item!)

He also said the plug issue is likely to have been caused by the Roc Euro intake, allowing the plugs to run hotter than spec due to the increased air flow, and has suggested l change all plugs to a higher specification.

I've got him replacing plug #3, and told him l want to see the old plug. I'll wait and see if fault has been cured before l change all plugs to a higher specification.

The RocE has been in place over a year.....

[pez81]

So, Master Tech has done his initial diagnosis and root cause - Misfire in cylinder 3, due (he thinks) to a problem with the spark plug. (Not a warranty item!)

He also said the plug issue is likely to have been caused by the Roc Euro intake, allowing the plugs to run hotter than spec due to the increased air flow, and has suggested l change all plugs to a higher specification.

I've got him replacing plug #3, and told him l want to see the old plug. I'll wait and see if fault has been cured before l change all plugs to a higher specification.

The RocE has been in place over a year.....

Least you're getting somewhere. So you in the td1 club or not

Sent from my XT1580 using Tapatalk

[RAF_S7]

Least you're getting somewhere. So you in the td1 club or not

Sent from my XT1580 using Tapatalk

Not mentioned yet.....

[pez81]

Not mentioned yet.....

Hopefully not then mate.

Sent from my XT1580 using Tapatalk

[RAF_S7]

Cylinder 3 plug. He checked some random others, and they are close to this condition.

[pez81]

Oh! Weren't you running lower grade fuel? I wonder if that's why? Before we spoke you were running 95/97 weren't you. Maybe the fuel was crap

Sent from my XT1580 using Tapatalk

[pez81]

I might check mine actually

Sent from my XT1580 using Tapatalk

[RAF_S7]

Oh! Weren't you running lower grade fuel? I wonder if that's why? Before we spoke you were running 95/97 weren't you. Maybe the fuel was crap

Sent from my XT1580 using Tapatalk

Yes, I'd been running regular unleaded. Changed to Tesco Momentum (99Ron) about 6 weeks ago.....

[RAF_S7]

Confirmed no TD1

Master Tech suggested if I come in with a turbo issue, to remove the RocE's before bringing it into the workshop.

[///M Traitor]

I recently tackled the spark plug installation in my 2013 S6 myself. I was suffering from a lot of misfires which did not throw any DTCs because the frequency of misfire was not enough to meet the OBD2 threshold maximum. Although I was able to reproduce the misfire with the accelerator and the correct driving conditions, it still was not enough misfires per 1000 revolutions to generate a DTC - however the drivability was terrible!

Low/to mid rpm high load conditions would create terrible performance and the car felt like it wasn't making any boost. I thought it was a boost leak for quite some time but there were none to be found. Strangely enough, full throttle and high rpms seemed fine. It turns out that it takes more spark energy at lower RPMs than at high RPMs and it's worst across the board when the cylinder pressure is high - who knew? That's counter intuitive to me.

Anyway, once I dug into the advanced measurement tables in the VAG COM I found the total misfire channels for each cylinder and started saving the log each time I would drive. I would force the car to reproduce the sluggish acceleration and check the logs and sure enough many more misfires were recorded. I was then convinced it was either plugs or coil packs. Since I had misfires on all cylinders, I figured I'd start with the plugs.

I was at 4 years and ~28k miles on the original factory plugs when I started feeling this poor part-throttle performance. I ended up using the OEM plugs with part number 06K905601M because my VIN provided to the audi parts department revealed that these are the NEW NEW NEW indicated spark plugs. The spark plugs for my car have been superseded 4 times now LOL. I was a bit disappointed that the plugs I got were top firing compared to the side-firing plugs that were factory installed, but the car certainly drives better now that I changed all of the plugs. I still think I may have a weak coil or two, but the difference in performance is astounding. I may be looking for problems at this point - that's how much it improved.

It was a major task to get to the spark plugs. I actually had to remove the air box on the passenger side, and the coolant reservoir on the driver side (meaning, siphon coolant out of the tank, and disconnect all hoses to remove it). Then, the solid wire looms and 25+ connectors, vacuum hoses, clips, etc (on each bank!) needed to be untangled and disconnected to gain access to the coil packs. The pictures in this album somewhat show the process (in no particular order). I wish I took more pictures, because the procedure is certainly worthy of a good DIY write-up with pictures.

The Flickr album is here: https://flic.kr/s/aHskUrahc9 Why can't I figure out how to embed this album?

[RAF_S7]

I recently tackled the spark plug installation in my 2013 S6 myself. I was suffering from a lot of misfires which did not throw any DTCs because the frequency of misfire was not enough to meet the OBD2 threshold maximum. Although I was able to reproduce the misfire with the accelerator and the correct driving conditions, it still was not enough misfires per 1000 revolutions to generate a DTC - however the drivability was terrible!

Low/to mid rpm high load conditions would create terrible performance and the car felt like it wasn't making any boost. I thought it was a boost leak for quite some time but there were none to be found. Strangely enough, full throttle and high rpms seemed fine. It turns out that it takes more spark energy at lower RPMs than at high RPMs and it's worst across the board when the cylinder pressure is high - who knew? That's counter intuitive to me.

Anyway, once I dug into the advanced measurement tables in the VAG COM I found the total misfire channels for each cylinder and started saving the log each time I would drive. I would force the car to reproduce the sluggish acceleration and check the logs and sure enough many more misfires were recorded. I was then convinced it was either plugs or coil packs. Since I had misfires on all cylinders, I figured I'd start with the plugs.

I was at 4 years and ~28k miles on the original factory plugs when I started feeling this poor part-throttle performance. I ended up using the OEM plugs with part number 06K905601M because my VIN provided to the audi parts department revealed that these are the NEW NEW NEW indicated spark plugs. The spark plugs for my car have been superseded 4 times now LOL. I was a bit disappointed that the plugs I got were top firing compared to the side-firing plugs that were factory installed, but the car certainly drives better now that I changed all of the plugs. I still think I may have a weak coil or two, but the difference in performance is astounding. I may be looking for problems at this point - that's how much it improved.

It was a major task to get to the spark plugs. I actually had to remove the air box on the passenger side, and the coolant reservoir on the driver side (meaning, siphon coolant out of the tank, and disconnect all hoses to remove it). Then, the solid wire looms and 25+ connectors, vacuum hoses, clips, etc (on each bank!) needed to be untangled and disconnected to gain access to the coil packs. The pictures in this album somewhat show the process (in no particular order). I wish I took more pictures, because the procedure is certainly worthy of a good DIY write-up with pictures.

The Flickr album is here: https://flic.kr/s/aHskUrahc9 Why can't I figure out how to embed this album?

What condition were the plugs in when removed?

Mine were all pretty nasty.

[///M Traitor]

What condition were the plugs in when removed?

Mine were all pretty nasty.

When I pulled them I thought they looked terrible! Caked on carbon, and the threads were packed with carbon too. And then I saw the plugs in this thread above and mine are not nearly that bad LOL. They were still missing like crazy though. I was wondering if I baby the car too much (I don't commute to work, and the majority of my miles are short trips where the car does not even reach full temp) but after seeing the plugs in this thread I'm doing pretty good I guess.. I'm not entirely convinced that the visual condition tells the whole story about the misfires and the cause. I think there's more to it than the carbon on the surface. The electrodes are clean after all.

[moonlights4]

When I pulled them I thought they looked terrible! Caked on carbon, and the threads were packed with carbon too. And then I saw the plugs in this thread above and mine are not nearly that bad LOL. They were still missing like crazy though. I was wondering if I baby the car too much (I don't commute to work, and the majority of my miles are short trips where the car does not even reach full temp) but after seeing the plugs in this thread I'm doing pretty good I guess.. I'm not entirely convinced that the visual condition tells the whole story about the misfires and the cause. I think there's more to it than the carbon on the surface. The electrodes are clean after all.

Interesting, you have described almost identically the problem I've been having for the past 3-4 weeks with my 2014. I took it to the dealer after having been flashed back to stock since it's under warranty and has AC, but they said everything is within spec and there were no error codes to be found, or significant abnormalities with driving it under some degree of logging.

You have me thinking that I should just take it down to a local Audi shop and have them change all the plugs next week! Not certain I have the time/wherewithal to DIY a plug change.

My car has 30k on it, so is right about where yours is.

Agree that low/mid throttle driveability is suffering even though I don't get any CELs

FWIW, Chris@EPL has also been telling me to get new plugs as well, so there seems to be a theme emerging here...


Sent from my iPhone using Tapatalk

[RAF_S7]

I'm about 1000 miles along the road since I changed mine, and its not missed a beat since, and it certainly feels much more responsive since the plugs were changed.

Plugs are a maintenance item, and the recommended change interval from Audi is 35,000. Interestingly if you have a tune, some suppliers recommend you change the plugs around every 15,000 miles.

A lot of us change our oil more often than the recommended service interval, and Im thinking maybe we should consider plugs one of those items that deserve a bit more attention than we have been giving them......

I dont have a tune, only the air intake and exhaust mods, but Im addicted to the pops, bangs and growl of the engine, so I tend to drive in dynamic and sports mode pretty much all the time. The stresses of that within the cylinder must take its toll on the plugs themselves, I think

[///M Traitor]

Interesting, you have described almost identically the problem I've been having for the past 3-4 weeks with my 2014. I took it to the dealer after having been flashed back to stock since it's under warranty and has AC, but they said everything is within spec and there were no error codes to be found, or significant abnormalities with driving it under some degree of logging.

You have me thinking that I should just take it down to a local Audi shop and have them change all the plugs next week! Not certain I have the time/wherewithal to DIY a plug change.

My car has 30k on it, so is right about where yours is.

Agree that low/mid throttle driveability is suffering even though I don't get any CELs

FWIW, Chris@EPL has also been telling me to get new plugs as well, so there seems to be a theme emerging here...


Sent from my iPhone using Tapatalk

Bad news, my car is still missing a bit. Highway speed, 60/70 mph, manual mode 7th gear, slow roll-in of the throttle, and I can feel the car struggle to build power and boost smoothly. I think the coil packs are weak. I'm going to continue to log the missfires and see if it's only a few cylinders now.

[moonlights4]

Bad news, my car is still missing a bit. Highway speed, 60/70 mph, manual mode 7th gear, slow roll-in of the throttle, and I can feel the car struggle to build power and boost smoothly. I think the coil packs are weak. I'm going to continue to log the missfires and see if it's only a few cylinders now.

Disappointed to hear that. Is it only noticeable on the highway or is it still occurring around town? Will be interested to hear what you find.


Sent from my iPhone using Tapatalk

[eurodaddy]

This might sound strange but early last year I installed a magnaflow exhaust on my 13' S6. It is tuned Giac stage 1. Had the RS7 intake on it and it ran fine. No problems what so ever. In August of last year I decided to cut out the center Magnaflow resonator and put in straight pipes and had removed the two one resonators on the down pipes when I originally installed the exhaust early last year. I removed the center resonator to get more sound. Save your money if your looking at a magnaflow exhaust for the S6. The sound is not there and the fitment isn't either. So since I removed the center resonator the car started to misfire on cylinder 2 and 5. I put back into stock mode and the same thing. I decided to change all the plugs to factory spec and installed APR down pipe as well. The car drove amazing for the first 30 minutes then again a warning on the dash not to exceed 6000rpm and would idle and drive rough in limp mode. I decided to try a couple things and put the stock airbox back on. Nothing changed. Same issue. So I put the Airbox back on. It had me baffled. I just kept thinking and I realized this all started when I cut the center magnaflow resonator out and put in the straight pipes. Of course this is all happening when I saw some videos of the APR down pipes on the stock S6 sport exhausts. Amazing sound by the way. So I decided to try something and picked up a 2016 RS7 sport exhaust. It fits the S6 perfectly with no modifications. This might sound strange as since that day I have never had another misfire and the car drives stronger and better than it ever has.


Sent from my iPhone using Tapatalk

[///M Traitor]

I'm sure it happens every time the rpm and requested torque is the same. It's easier to feel in the higher gears though because the RPMs are in the trouble range longer

[///M Traitor]

I'm sure it happens every time the rpm and requested torque is the same. It's easier to feel in the higher gears though because the RPMs are in the trouble range longer

OK, I pulled the total misfire logs again and it's looking like a huge improvement so far. Only about 2~5 misfires per cylinder in the last 100 miles, and I changed the plugs somewhere in there. Now that I have a baseline log with the new plugs, I'll drive it some more and try to produce the sluggish behavior and check the misfire counts to see if they have increased. It's a cumulative count. It never resets. I have almost 200 misfires on cylinder 5! I asked my cousin what's a normal count for misfires, because he's been a ford master tech for many many years, and his reply was "zero" LOL.

Here is what the VagCom log looks like:

Address 01: Engine (4G0 906 014 B)

16:25:59
IDE01975 Number of misfires: cylinder 1 92
IDE01976 Number of misfires: cylinder 2 156
IDE01977 Number of misfires: cylinder 3 99
IDE01978 Number of misfires: cylinder 4 35
IDE03363 Number of misfires: cylinder 5 191
IDE03364 Number of misfires: cylinder 6 82

[moonlights4]

OK, I pulled the total misfire logs again and it's looking like a huge improvement so far. Only about 2~5 misfires per cylinder in the last 100 miles, and I changed the plugs somewhere in there. Now that I have a baseline log with the new plugs, I'll drive it some more and try to produce the sluggish behavior and check the misfire counts to see if they have increased. It's a cumulative count. It never resets. I have almost 200 misfires on cylinder 5! I asked my cousin what's a normal count for misfires, because he's been a ford master tech for many many years, and his reply was "zero" LOL.

Here is what the VagCom log looks like:

Address 01: Engine (4G0 906 014 B)

16:25:59
IDE01975 Number of misfires: cylinder 1 92
IDE01976 Number of misfires: cylinder 2 156
IDE01977 Number of misfires: cylinder 3 99
IDE01978 Number of misfires: cylinder 4 35
IDE03363 Number of misfires: cylinder 5 191
IDE03364 Number of misfires: cylinder 6 82

Thanks for sharing. Glad to hear that there was improvement with the new plugs, looks like it may be more specific to 2 and 5 now. Maybe you are right about a weak coil or two. I'll probably go ahead and get my plugs replaced this week based on what you've found so far.


Sent from my iPhone using Tapatalk

[///M Traitor]

Update: I did some local driving with mixed driving style (babying it, launching it, and some manual mode high gear lugging pulls which usually cause misfires). I only felt a few, and the vagcom log confirms that there were only a few misfires. The car feels SO much better since I changed the plugs, but I still think there's a bit of room for improvement.

This is my baseline log after changing the plugs:

Address 01: Engine (4G0 906 014 B)

16:25:59
IDE01975 Number of misfires: cylinder 1 92
IDE01976 Number of misfires: cylinder 2 156
IDE01977 Number of misfires: cylinder 3 99
IDE01978 Number of misfires: cylinder 4 35
IDE03363 Number of misfires: cylinder 5 191
IDE03364 Number of misfires: cylinder 6 82
IDE03365 Number of misfires: cylinder 7 63
IDE03366 Number of misfires: cylinder 8 76


And then 25 miles later taken today:

Address 01: Engine (4G0 906 014 B)

14:39:52
IDE01975 Number of misfires: cylinder 1 92
IDE01976 Number of misfires: cylinder 2 157
IDE01977 Number of misfires: cylinder 3 100
IDE01978 Number of misfires: cylinder 4 35
IDE03363 Number of misfires: cylinder 5 194
IDE03364 Number of misfires: cylinder 6 82
IDE03365 Number of misfires: cylinder 7 63
IDE03366 Number of misfires: cylinder 8 77

Only cylinders 2, 3, 5 and 8 are reporting misfires with cyl 5 being the worst. I'm going to keep an eye on cylinder 5....

[RAF_S7]

Are these values always accumulative, with no way to reset to zero?

Id consider swapping cylinder 5 and cylinder 4 coils around, just to see if the fault moves from 5-->4 That way you know you have a bad coil and to consider a swap out. You will likely find that the coil packs have been superseded a few times, a bit like your plugs.

[pez81]

I'm no expert on this but could it be the injectors or fuel lines? Don't running lean cause these too?

Sent from my XT1580 using Tapatalk

[///M Traitor]

I haven't found a way to reset the misfire count. They are cumulative.

I wish I had the foresight to swap the coil packs while I was in there doing the plugs. Depending on where cyl 5 is, it might be a huge undertaking. How are the cylinders numbered? Is there a diagram?

[tenspeed]

How are the cylinders numbered? Is there a diagram?

Found this on Wikipedia - section 2
"In most Audi and Ford V8 engines cylinders 1-2-3-4 are on the right hand side of the car, with 5-6-7-8 are on the left."

https://en.wikipedia.org/wiki/Firing_order

[P_G]

RAF, how are you getting on with the plug change and premium fuel now, any issues?


Sent from my iPad using Tapatalk

[RAF_S7]

RAF, how are you getting on with the plug change and premium fuel now, any issues?

No more issues, and significant improvement in engine response as well.

I put through a bottle of Wynn's premium injector cleaner and have switched to Shell Ultra Nitro+.

Very happy now

John.

[moonlights4]

Great to hear, I may delay my spark plug replacement until May, as I realized that I am due for the 35k service under AC at that time, so it seems silly to go to the trouble/expense to replace the plugs only to do it again in four weeks. Will let you know what happens after I get them replaced then. Thank you for the insight!