Bad NGKs?

[pearlpower]

Multiple misfires. Yes, The gap was set to .020. I need to scope the bores now. Total of 4 plugs bad within 2k miles. Picture of 2 of them are attached. 95770 NGK.

[X5 MAN]

Could be coils going bad.

[pdX5M]

If you end up replacing the plugs and coils go with the NGK 97506 gapped to 0.020". I'm also running Velos Stage 2 and have been running these plugs for the past 6k miles and they've been great.

[Sophisticated Redneck]

Looks like the electrode was burned off, that is usually a sign of severe pre-detonation or super lean air/fuel mixture. Definitely borescope every cylinder, Amazon has a few borescopes with dual cameras in the head, one at 90 degree makes it super easy to see cylinder wall conditions.

Like pdx said, I would recommend going to 97506 if you have a tune or back to Bosch plugs If your stock then run fuel injector tests in ISTA. If Injectors come back ok, then run an app like torque so you can watch air fuel mixture and fuel rail pressure to monitor HPFP's.

Also if it were me, I would just replace both of your pre-cat oxygen sensors right now If they are the originals and especially since they are so easy to do on the S63. The kind of cylinder temps that will melt an electrode will ruin an engine and it's worth the peace of mind knowing that it is one less variable.

Quick question, were all four plugs bad on the same bank? If so I would be highly suspect of the HPFP or oxygen sensor on that bank.

[mitch808]

The pitting on the first plug, and the brown ash color on the other are signs of something else going on. e.g. Coils, fuel injectors, valve issues, etc; are all reasons for those plugs to fail like that.

[pearlpower]

I recently swapped my Bosch coils for Eldors due to coil issues, could be plugs were going south with the Bosch coils. I will put in my backup plugs once I run my scope through it. I have several around here for this purpose. Else, perhaps I ended up getting fake NGK plugs.

[Dawgz]

Fake NGKs are all over eBay. Where did you get it?

[pearlpower]

I scoped the bores and I lucked out, they look great, even my pistons have minimum carbon buildup. For now I put back the prior Bosch double plats back in and new Eldor coils, and it pulls strong and hard. Idle is smoother. I used my scanner and checked misfires for each cylinder and there were no spikes, whereas cylinder 1&2 had 2300 and 1026 recorded misfires compared to an average of 30 for the rest, prior. I ordered new Bosch plugs. I'm going to surmise mu Bosch coils took out the plugs, but at the same time, given how fake NGKs are so prevalent, I am going to steer away from them. Yes, yes, buy from a reputable vendor, etc, etc.

[Dawgz]

Originally Posted by pearlpower

I scoped the bores and I lucked out, they look great, even my pistons have minimum carbon buildup. For now I put back the prior Bosch double plats back in and new Eldor coils, and it pulls strong and hard. Idle is smoother. I used my scanner and checked misfires for each cylinder and there were no spikes, whereas cylinder 1&2 had 2300 and 1026 recorded misfires compared to an average of 30 for the rest, prior. I ordered new Bosch plugs. I'm going to surmise mu Bosch coils took out the plugs, but at the same time, given how fake NGKs are so prevalent, I am going to steer away from them. Yes, yes, buy from a reputable vendor, etc, etc.

Fcpeuro has them and you can be sure they won't be fakes