Cylinder 7 Misfire

[scottgps92]

Hey Guys, I'm new to the F10 game but learning much! Just came from a built S/C E39 M5, but these are two different beasts!

I recently put on catless downpipes, meth, 3.5 MAP sensors and rk tune. So far it drives good, but the last couple days I was able to mash the throttle and BAM!! drivetrain malfunction full power not available. After restarting it went away but engine light was on. I checked it said cylinder 7 misfire, so as usual I cleared and tried again, didn't do it for a day but came back today with same issue.

Btw, this only happens when flooring gas in 3rd and 4th gear, 3.5-4.5k rpm (haven't tried any higher), if I let it slowly climb to that and above its perfectly fine.



My guess its a ignition coil (so thats on order right now, also not sure when the coils were last replaced), but before I dig in to replace it I wanted to double check to make sure I'm not missing something else.

Spark plugs are brand new, gapped to the stock 0.034, not sure if that could be a issue?

Thanks!- Scott

[13M5F10]

Originally Posted by scottgps92

Hey Guys, I'm new to the F10 game but learning much! Just came from a built S/C E39 M5, but these are two different beasts!

I recently put on catless downpipes, meth, 3.5 MAP sensors and rk tune. So far it drives good, but the last couple days I was able to mash the throttle and BAM!! drivetrain malfunction full power not available. After restarting it went away but engine light was on. I checked it said cylinder 7 misfire, so as usual I cleared and tried again, didn't do it for a day but came back today with same issue.

Btw, this only happens when flooring gas in 3rd and 4th gear, 3.5-4.5k rpm (haven't tried any higher), if I let it slowly climb to that and above its perfectly fine.



My guess its a ignition coil (so thats on order right now, also not sure when the coils were last replaced), but before I dig in to replace it I wanted to double check to make sure I'm not missing something else.

Spark plugs are brand new, gapped to the stock 0.034, not sure if that could be a issue?

Thanks!- Scott

From my experience, you'll need to gap the plugs down to supported the higher boost levels. Since you'll be gapping the plugs I would replace #7 and all 8 coil packs.

[ur20v]

Agreed, first step is to replace and gap the plugs and fit new coils.

Most MAL's for this reason happen in the very high torque range 3-5k rpm.

You should be ok then.

Do you have a JB4 or other device to log - its worth check everything is where it needs to be and logging certainly helps support and finding issues.

[ur20v]

What controls your meth and where does your meth kick in and how much are you throwing at it?

You could be dumping to much in to early.

[scottgps92]

Alright, what should I gap the new plugs too? I'll get those coils ordered asap!

No JB4, I do have a PLX kiwi i'll have to check to see what it can log.


I have a AEM controller, which kicks on at 15psi and flows full at 15psi. I already tried turning off the meth and running it, same thing happens.

[13M5F10]

Originally Posted by scottgps92

Alright, what should I gap the new plugs too? I'll get those coils ordered asap!

No JB4, I do have a PLX kiwi i'll have to check to see what it can log.


I have a AEM controller, which kicks on at 15psi and flows full at 15psi. I already tried turning off the meth and running it, same thing happens.

Your tuner RK should tell you what to gap to. My M5 was gapped to .018 while others on here are gapping to .022. Both have shown to work so I wouldn't be too worried about which to go with. Hopefully a tuner can chime in with their recommendations.

[13M5F10]

Originally Posted by scottgps92

Alright, what should I gap the new plugs too? I'll get those coils ordered asap!

No JB4, I do have a PLX kiwi i'll have to check to see what it can log.


I have a AEM controller, which kicks on at 15psi and flows full at 15psi. I already tried turning off the meth and running it, same thing happens.

With PLX you should be able to use the Torque app which has data logging capability

[ur20v]

Mine are gapped at 22, but as 13M5F10 said I don't think it matters, just replace the coils as well as they do knock detection plus can become faulty from missfire loads caused by large gaps on plugs- keeping plugs fresh ~10kmiles max and gapped will avoid this

[scottgps92]

Alright thanks guys! New plugs and coils on order, will put them in over the weekend. I'll update once they are in!

[BPMSport]

Originally Posted by ur20v

Mine are gapped at 22, but as 13M5F10 said I don't think it matters, just replace the coils as well as they do knock detection plus can become faulty from missfire loads caused by large gaps on plugs- keeping plugs fresh ~10kmiles max and gapped will avoid this

What makes you think the coils perform knock detection on this platform?

[schnell1982]

Originally Posted by scottgps92

Alright, what should I gap the new plugs too? I'll get those coils ordered asap!

No JB4, I do have a PLX kiwi i'll have to check to see what it can log.


I have a AEM controller, which kicks on at 15psi and flows full at 15psi. I already tried turning off the meth and running it, same thing happens.

Instead of throwing money at the car, take 1 step back and swap the ignition coil from #7 to #3 for example. Clear the code and see when it comes back. If it follows the cylinder you moved it to, its a coil.
If it stays then check the plug and move on from there.
Make sure to clear the codes before so that you are documenting what is going on.

[scottgps92]

Update:

Replaced all the coils and plugs gapped to .022, no more misfires!! Also adjusted meth to kick in at 15psi and run full spray at 20psi.

Still debating weather to keep the meth at 100% or run 50/50, its not tuned for meth.

[ur20v]

What is controlling your meth and what boost are you running.

[scottgps92]

AEM meth controller (based on PSI) and running 25psi boost

[ur20v]

If you can log, you can do runs and see where your fuel trims end up at 50/50 mix th go up from there if required.