Misfires again with new spark plugs

[MyDimeIsUp]

This is a continuation from my previous old thread back in October (https://www.audizine.com/forum/showt...-on-cylinder-2)

I was out driving yesterday and felt the car stammering, almost like a misfire while under load. I plugged in my OBD11 and saw a misfire on cylinder 3. I presume it is the spark plugs again since back in October when I threw new NGK plugs in the misfire went away until recently. I haven't pulled plugs yet but I would assume there is going to be the same black soot on the ground strap (pictured here from back in October). I don't imagine my oil burning would lead to this severe of ruining spark plugs. For the first 23k miles I had the car I was burning 1qt/1,700 miles and the plugs were original until replaced them in July of 2022. Then October 2022 is when I was getting misfire codes and I created that thread and threw another set of NGK plugs in, which fixed the misfire codes. I'm running KIT-06H905601AKT2 (NGK# PFR7S8EG) from FCPEuro

What do you think this could be? I'm now burning 1qt/1,200 miles but that does not seem nearly enough to ruin plugs this fast. Could it be bad coil packs that aren't giving the plugs enough voltage hence some leftover byproducts in the combustion chamber are being coaked onto the ground strap? How come this soot is only on the ground strap and not the electrode?

Again I'll update when I pull my cylinder 3 plug and snap an photo but want to get some ideas of if this could be bad coil packs. I'm still running original coil packs with 159k miles.

[JLAllroad]

This is a continuation from my previous old thread back in October (https://www.audizine.com/forum/showt...-on-cylinder-2)

I was out driving yesterday and felt the car stammering, almost like a misfire while under load. I plugged in my OBD11 and saw a misfire on cylinder 3. I presume it is the spark plugs again since back in October when I threw new NGK plugs in the misfire went away until recently. I haven't pulled plugs yet but I would assume there is going to be the same black soot on the ground strap (pictured here from back in October). I don't imagine my oil burning would lead to this severe of ruining spark plugs. For the first 23k miles I had the car I was burning 1qt/1,700 miles and the plugs were original until replaced them in July of 2022. Then October 2022 is when I was getting misfire codes and I created that thread and threw another set of NGK plugs in, which fixed the misfire codes. I'm running KIT-06H905601AKT2 (NGK# PFR7S8EG) from FCPEuro

What do you think this could be? I'm now burning 1qt/1,200 miles but that does not seem nearly enough to ruin plugs this fast. Could it be bad coil packs that aren't giving the plugs enough voltage hence some leftover byproducts in the combustion chamber are being coaked onto the ground strap? How come this soot is only on the ground strap and not the electrode?

Again I'll update when I pull my cylinder 3 plug and snap an photo but want to get some ideas of if this could be bad coil packs. I'm still running original coil packs with 159k miles.

I generally only run my coils for 50k miles (tuned), otherwise I would have probably replaced them at 100k proactively, OE Denso’s from FCPeuro.

That said, you need a rebuild, the consumption will only get worse and you’re already essentially replacing an entire oil change worth, between oil changes. Probably looking at a clogged catalytic converter and not great for the O2 sensors.


Sent from my iPhone using Audizine Forum

[bb-tt]

This is a continuation from my previous old thread back in October (https://www.audizine.com/forum/showt...-on-cylinder-2)

I was out driving yesterday and felt the car stammering, almost like a misfire while under load. I plugged in my OBD11 and saw a misfire on cylinder 3. I presume it is the spark plugs again since back in October when I threw new NGK plugs in the misfire went away until recently. I haven't pulled plugs yet but I would assume there is going to be the same black soot on the ground strap (pictured here from back in October). I don't imagine my oil burning would lead to this severe of ruining spark plugs. For the first 23k miles I had the car I was burning 1qt/1,700 miles and the plugs were original until replaced them in July of 2022. Then October 2022 is when I was getting misfire codes and I created that thread and threw another set of NGK plugs in, which fixed the misfire codes. I'm running KIT-06H905601AKT2 (NGK# PFR7S8EG) from FCPEuro

What do you think this could be? I'm now burning 1qt/1,200 miles but that does not seem nearly enough to ruin plugs this fast. Could it be bad coil packs that aren't giving the plugs enough voltage hence some leftover byproducts in the combustion chamber are being coaked onto the ground strap? How come this soot is only on the ground strap and not the electrode?

Again I'll update when I pull my cylinder 3 plug and snap an photo but want to get some ideas of if this could be bad coil packs. I'm still running original coil packs with 159k miles.

what did you gap the plugs at? the pics of the plugs dont look bad at all. are you tuned? if so what tune? when you pull the plug to check it swap #1 and #3 coil and see if the misfire swaps.

[MyDimeIsUp]

I generally only run my coils for 50k miles (tuned), otherwise I would have probably replaced them at 100k proactively, OE Denso’s from FCPeuro.

That said, you need a rebuild, the consumption will only get worse and you’re already essentially replacing an entire oil change worth, between oil changes. Probably looking at a clogged catalytic converter and not great for the O2 sensors.


Sent from my iPhone using Audizine Forum

Personally 1qt/1,200 miles is somewhat fast I'm still inclined to let it go for a little longer. I've been looking into doing an engine rebuild over the summer depending on how things go (I may have an internship in another state for 10 weeks) so I'll figure it out. Even then I don't think the oil consumption is fast enough to be burning plugs every 3,000 - 4,000 miles considering the original plugs lasted to 153k without any problems (I replaced them as preventative maintenance last summer).

what did you gap the plugs at? the pics of the plugs dont look bad at all. are you tuned? if so what tune? when you pull the plug to check it swap #1 and #3 coil and see if the misfire swaps.

Stock everything. I didn't regap the plugs so they should be at the original spec that NGK sends them out 0.028 - 0.032. I should probably pick up a gap gauge at AutoZone just to be sure when I pull the spark plug out.

[RPMtech147]

I wouldn't go any further until you throw a set of coils at it. I know. Audi coils suck. (Really they're better than most..they have their own 12V supply that's not supplied from the DME/ECU..looking at you, BMW.)

[bb-tt]

I wouldn't go any further until you throw a set of coils at it. I know. Audi coils suck. (Really they're better than most..they have their own 12V supply that's not supplied from the DME/ECU..looking at you, BMW.)

I have been using audi(eldor) coils for the r8 in my b8 since 2018 without a single issue.

[bb-tt]

Personally 1qt/1,200 miles is somewhat fast I'm still inclined to let it go for a little longer. I've been looking into doing an engine rebuild over the summer depending on how things go (I may have an internship in another state for 10 weeks) so I'll figure it out. Even then I don't think the oil consumption is fast enough to be burning plugs every 3,000 - 4,000 miles considering the original plugs lasted to 153k without any problems (I replaced them as preventative maintenance last summer).



Stock everything. I didn't regap the plugs so they should be at the original spec that NGK sends them out 0.028 - 0.032. I should probably pick up a gap gauge at AutoZone just to be sure when I pull the spark plug out.

omg always check the gap before installing! if you are tuned you want to be at .028 if k04 at least down to .026

[MyDimeIsUp]

omg always check the gap before installing! if you are tuned you want to be at .028 if k04 at least down to .026

FCPEuro only has Denso R8 coil packs, no Eldor coils, but I've heard Denso is a reliable OEM. Gonna buy those. I swapped Cyl 3 and 2 coils and had it misfire once today so I plugged in my OBD11 but couldn't replicate it even under load. It seems to be not as bad right now but occasionally misfires when under load. Even went to a really steep hill with 1/2 - 3/4 throttle but couldn't get it to misfire again so I'm unsure if the misfire has moved to Cyl 2.

[silver_tt]

Denso is a good brand of plugs. Used their Iridiums in my 911 TT, very good plug...

[MyDimeIsUp]

Denso is a good brand of plugs. Used their Iridiums in my 911 TT, very good plug...

I meant coil packs oops! I've edited my post

[bb-tt]

FCPEuro only has Denso R8 coil packs, no Eldor coils, but I've heard Denso is a reliable OEM. Gonna buy those. I swapped Cyl 3 and 2 coils and had it misfire once today so I plugged in my OBD11 but couldn't replicate it even under load. It seems to be not as bad right now but occasionally misfires when under load. Even went to a really steep hill with 1/2 - 3/4 throttle but couldn't get it to misfire again so I'm unsure if the misfire has moved to Cyl 2.

i bought at dealer they were really not that expensive, but that was 2018.

[JLAllroad]

i bought at dealer they were really not that expensive, but that was 2018.

Don’t you mean 1820?


Sent from my iPhone using Audizine Forum

[imthecleanup]

Have you considered replacing your fuel injectors? My car misfired until I replaced them.

[Grouch]

FCPEuro only has Denso R8 coil packs, no Eldor coils, but I've heard Denso is a reliable OEM. Gonna buy those. I swapped Cyl 3 and 2 coils and had it misfire once today so I plugged in my OBD11 but couldn't replicate it even under load. It seems to be not as bad right now but occasionally misfires when under load. Even went to a really steep hill with 1/2 - 3/4 throttle but couldn't get it to misfire again so I'm unsure if the misfire has moved to Cyl 2.

FCEuro carries OEM R8 coils, just not as a pack. https://www.fcpeuro.com/products/aud...reg-06e905115e

I use these in my car with no issues.

[JLAllroad]

FCEuro carries OEM R8 coils, just not as a pack. https://www.fcpeuro.com/products/aud...reg-06e905115e

I use these in my car with no issues.

Take note of the part# of the coil on the R8 coil kit

https://www.fcpeuro.com/products/aud...06e905115ekt17


Sent from my iPhone using Audizine Forum

[Grouch]

Take note of the part# of the coil on the R8 coil kit

https://www.fcpeuro.com/products/aud...06e905115ekt17


Sent from my iPhone using Audizine Forum

Huh TIL. So they make parts for VAG and make their own aftermarket ones too? Surprised that's somehow legal.

[JLAllroad]

Huh TIL. So they make parts for VAG and make their own aftermarket ones too? Surprised that's somehow legal.

Very common for the OEM to make branded(Audi) and private label(Denso).

This can allow for significant savings when available.


Sent from my iPhone using Audizine Forum

[MyDimeIsUp]

Car has decided to be misfire free for the past couple of days. I'll update when it misfires again and see if the misfire has moved.

[bb-tt]

FCEuro carries OEM R8 coils, just not as a pack. https://www.fcpeuro.com/products/aud...reg-06e905115e

I use these in my car with no issues.

eldor was the oem
looks like fcp has eldor for 29 each
Audi Porsche VW Ignition Coil - Eldor R0602S00300

[Grouch]

eldor was the oem
looks like fcp has eldor for 29 each
Audi Porsche VW Ignition Coil - Eldor R0602S00300

Good looking out. Saving this to my list for next time.

[MyDimeIsUp]

Did a 45 mile drive each way on PA backroads. Started the car up and misfired 3 times every 10 seconds while idling. During the drive to and from though it was misfire free even under load. Misfire is still on cylinder 3 and did not move to cylinder 2 when I swapped the coils.

[Mikel147]

TLDR: OP have you cleaned your intake valves?

[MyDimeIsUp]

I have not but I took a video with my borescope through the intake air temp hole (I removed the sensor) and at 159k they really didn't look that bad, but I was only able to get one of the valves from cylinder 1 visible, not sure what the rest look like. The misfire was also only on cylinder 3, the one that has misfires when under load.

Also it misfires most when in 6th or 7th gear below 2k rpm and giving it about 1/6" to 1/8" throttle.

[JLAllroad]

Did a 45 mile drive each way on PA backroads. Started the car up and misfired 3 times every 10 seconds while idling. During the drive to and from though it was misfire free even under load. Misfire is still on cylinder 3 and did not move to cylinder 2 when I swapped the coils.

Idle misfires often indicate vacuum leaks. PCV, RMS or otherwise.

That said, did you check compression?


Sent from my iPhone using Audizine Forum

[MyDimeIsUp]

Idle misfires often indicate vacuum leaks. PCV, RMS or otherwise.

That said, did you check compression?


Sent from my iPhone using Audizine Forum

I haven't no but I highly doubt this is a compression issue. Also no oil leaks around RMS though I haven't sprayed brakecleen by it. PCV seems fine as I replaced it about 1 1/2 years ago and I don't feel any vacuum/sucking on the little port on the side of the black hockey pock part.

Here's an Imgur album of the cylinder 3 plug I pulled, which is misfiring. The plug came from FCPEuro and is PFR7S8EG, with "VW AG" and "NGK" on the outside of the ceramic. They have about 5 months and 3k - 5k miles on them.

https://imgur.com/a/5Lzbv0b