OBD 11 FALLS well short of giving the full info but the codes themselves are shown. The next step in the codes are the capture data that comes with it.
Grab the trim data and then see if it’s specific to that bank. remember there are 4 banks. not just two
Ross Tech has the ability to watch all 10 cylinders and keep a count of which cylinder misfires. Seemed very helpful for me to be able to see exactly which cylinders and at which moment it was happing rather than just seeing a CEL code when it decides to throw a code.
It only misfires on the very same cylinder every time(Cyl2). Which is also why I doubt its the cat, as I would see misfires on Cyl1 aswell then. The freeze frame data that comes with the code is quite usless, just shows date and milages, not sure whether this is because of obdeleven or the ECU.
It’s because its obd11 that freeze data is just about usless. That’s why I was saying vag com shows real data. Load / RPM / Throttle / and other snap shot data of the event that can help track down. In the end. It’s not the end of the world but usually the vag com freeze frame data can give you a window into when the event is really happening other than when it appears its happening.
It still could be the cat but unlikely as mentioned due to not seeing more events on the other cyl still in some cases the misfire buffer on some cylinders is higher than others.
Could it potentially be leaking air through the intake manifold gasket, messing up the intake air volume? And recommended action is a smoke test? (Sorry if its a stupid suggestion, im still quite new at this)
A couple of easy things to do:
If it stays with the cylinder you know neither is the cause. If it moves then you have a possible suspect. Do this one at a time.
Ed
I’ve already done that, no joy, sadly.
OK so you know it’s most likely not the coil or spark plug.
The next swap would be the injector, but that is a PITA.
Ed
Take compressions to see if there is a problem on this cylinder specifically.
At that point an easy next step test before you start taking things apart would be the smoke test. This usually will help give an idea on what your working with. It’s possible to have an entire bank that is getting un metered air and only have one missfire cylinder. This leads back to injectors and the flow rate. It’s not uncommon to have even new non Audi specific replacement injectors under flow by 10 - 20%
have you checked the resistance of the throttle body cables?
I have not, you thinking it does open fully ? Restricting air flow?
PS: Just did compression test on all sylinders, decent results.
just that I had some issues similar to this on my RS5 and it couldn’t even drive round the corner to the shops…was throwing up weird issues too like handbrake warnings etc…turned out to be the throttle body cables.
If the car has a tune, it will need ARP coils and better plugs. You can buy one coil and plug, and test it against the OEM. On tuned cars, the coils and plugs should always be replaced with ARP, as the tune will want more power to light up. Its common to replace them, and misfires do occur with tunes due to this reason.
FYI. My RS7 misfires on 5+6 periodically (I see the error codes), and I intend to replace them with ARP coils and plugs soon.
While it’s always a good idea to replace your plugs and re-gap them down and get a colder plug. The APR coil packs are totally not needed. A good NKG replacement coil pack is more than enough.
The RS7 has a TSB for a misfire on cylinders 5 and 6. They fix it with a ECU update. unless you have the weak spring issue then the ECU update isn’t going to help.
The TSB is on Cyl 5 only … not Cyl 6.
I do not think an APR tune will work with this ECU fix, regardless … I suspect the ECU fix is to turn down the boost at higher RPMs.
Now why would anyone want to put a band-aid on a spring, with a shim … is beyond me.
Back to my issue … its 5+6 … so maybe or maybe not the TSB applies … regardless … I am not putting in a shim … I would rather replace them with new injectors and heavier springs … as the issue noted in the TSB seems to be float issues … by using the spring plate … you shim it … plus the ECU probably tones down the turbo at higher RPMs.
I have not addressed this yet … this summer … but if I am going to dig this deep into the motor … I am going to put back new injectors + APR coils + better NGK plugs + APR or Ferrara Springs
The TSB just desensitizes the misfire trigger for those cylinders in the ECU update for the RS7 and S8. Cylinder 5 and on some cars 6 will be an issue. Regardless of if you see it in the TSB. 6 is less common but still on some cars pre ECU update an issue.
I agree, maybe a shim isn’t a great real fix that I’d want to see.
Lastly I do agree. APR coils are totally not needed. If you like them. Get them but they don’t really make a difference and are totally not needed. Standard NGK replacement coils are more than enough for serious hp. On all cars not just the RS7
I agree with all of your statements … and the shim fix on the TSB sounds suspect … plus it is an alum spring seat … which I can only assume would eventually marry to the head … I have cyl 5+6 misfire periodically … it all depends how I drive the car … and believe the issue is either the coils are not hot enough or the plugs … or the real cause is the springs and floating at higher rpms and boost.
That said … next week, I am going to have all the fluids replaced, and need the rear diff fluid checked … at this time … I will go over with the mech all my future plans for the car … and this is what I sum it up as.
NOTE: I have an ARP tune but am missing the dongle … so I will want this as well.
Stainless Braided Turbo Oil Line and Strainer/Screen Relocation Kit - C7 S6-S7-RS7, D4 A8-S8 4.0T
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APR Valve Springs/Seats/Retainers - Set Of 32
Manufacturer: ARP
$1,300 (approx)
APR RED IGNITION COIL 8 PACK WITH SPARK PLUGS (NGK R7437-8) (NGK R7437-9)
SKU MS100219-PLUG-8PK
$703.52
APR recommends NGK heat range 9 (NGK-R7437-9) spark plugs gapped to 0.024" ±0.002" or 0.6mm ±0.05mm with a change interval of 10-15,000 mi
APR Mobile Bluetooth Dongle
SKU EM100032
$220.95
My question is the following … and please respond if you know the ans.
If I want to have a display system like the Edge CTS3 (Insight) … which I have in my diesel truck … are there any manufacturers that have such a system that is plug in … and can show me the display like an Edge?
Hi, so I did a little trip just now, and took notes of LTFT and STFT. Was hoping for your wisdom and opinion.
ECM1 LSFT:
ECM2 LSFT:
Misfire range:
The STFT was during warm idle between 0 and -3%. During pull(and misfire) it was ranging between -7% and -11% on that one bank.
What are engine healthy numbers? Specially during load/rpm, do you know?
PS: All the sparkies had quite a bit carbon on them, but since i recently took over the car, I cant tell for certain it is due to running rich or simply if the previous owner did ALOT of small trips and such.
Just doing some thinking out loud, do correct my logic if it is indeed flawed.
All 10’s appear to run rich, if the fouled sparkies is indeed a symptom of that, and not small repetative driving. So if the sparkies confirm the rich condition, that suggests O2’s are operational.
Now if the fuel rail were leaking, sparkies wouldnt be fouled either, so ruling that out. Leaking fuel injector? Surely a possibility, but all 10 of them? Improbable.
What affects all 10’s somewhat “equally?” Manifold leak? A vacuum leak should cause a lean condition no? So not that.
So, potentially defect MAF? Could indeed cause all 10 to run rich, but why the variance between the banks? Only thing I can think of is, either MAF/Carbon Buildup causes rich condition, whilst Cyl2 has restricted airflow, potentially a broke flap piece jammed in the valve, which then corrupts the readings on the bank? As far as I can tell thats one of the few explianations.
Think I will buy a boroscope and shove it in, see whats what inside. Thoughts?
Solved the issue, but figured I might write incase anyone at some point have similar issues.
I noticed a tiny leak in the fuel regulator on the HPFP, ordered a new one, suspecting this could cause a too high pressure in the rail, and bleed over on the other rail aswell. Replaced the HPFP.
The misfire did not go away, but the rich condition was better. Proceeded to carbon clean the intake ports/valves/plugs, despite it being done recently, due to rich condition possibly accelerating the buildup. Swapped the misfiring injector with a to misfire moved or not.
Just did a testdrive, the misfire was gone, thankfully. I have no idea why tho, so I guess that remains a mystery for the ages. Could be on reinstall, something was sealed properly versus earlier or something. The carbon buildup was pretty minimal, so should be far away from causing misfires. I guess when in doubt, just carbon clean.
