Need help with misfire and cracking plugs on new build

scottygrape · 04-30-2023, 08:47 AM

Hello all,

Been having a weird issue with my car. This is a completely new build. Built motor, pure 750, Dorch stage 2, lift kit, m5 eu5 injectors, Nexsys b58 coil kit, e85 flex fuel custom tune by Chris Kontos.

We were in the process of going through revisions and all was well. We were at 27-28psi. I did a clean 4th gear pull. 5 minutes later did another pull and it started misfiring really bad under high load. Bunch of codes for Misc misfire. There is nothing weird in the logs. Fuel pressure and AFRs are perfect. Minimal timing corrections.

Upon troubleshooting and investigation I have now cracked 4 different spark plug insulators on all different cylinders. I am using ngk 97506 gapped to .026”. I am torquing them properly with a swivel to ensure I am not cracking the insulators on install. Anyone have any advice? Here are some logs and pics.

Here is a clean log https://datazap.me/u/scottygrape/cle...og=0&data=3-15

Here is a log of the misfire https://datazap.me/u/scottygrape/4th...og=0&data=3-15

thejeremyman9 · 04-30-2023, 10:33 PM

Usually happens with counterfeit NGKs. Where did you buy them from? You could try some OEM plugs and gap down if needed.

scottygrape · 05-01-2023, 05:02 AM

Quote:

Originally Posted by thejeremyman9

Usually happens with counterfeit NGKs. Where did you buy them from? You could try some OEM plugs and gap down if needed.

I get all my plugs from FCP euro.

yupetc · 05-01-2023, 09:23 AM

I've had similar issue where the porcelain base at the bottom came loose from the hex housing, causing misfires and random limp modes. Got real lucky because I couldn't find anything wrong with the car for few weeks then decided to start from the ground up by replacing parts which could be a suspect. On my first go was the sparkplugs and I realized I didn't pay attention to the sparkplug body before, always only looking at the ignition tip. So got real lucky to locate the loosened porcelain on the non-cylinder side of things. No more issues ever after.

For cracked sparkplug housing, I've never personally dealt with, but back in the olden days where I've apprenticed under some Toyota MR2 guru's, there were cracking sparkplug issues on VERY high boost. I do not remember the numbers, but I vaguely recall that a combination of high boost, cylinder firing shockwave, can contribute to cracking it. This is over 20 years ago, so I couldn't go further remembering. Sub'd for more discoveries and a learning curve for myself.

scottygrape · 05-02-2023, 04:39 AM

So I ended up switching to b58 spark plugs and the issue is now fixed. So weird.

yupetc · 05-02-2023, 09:11 AM

Quote:

Originally Posted by scottygrape

So I ended up switching to b58 spark plugs and the issue is now fixed. So weird.

Glad that's been addressed. Seems like you're having quite a handful on this build. Hope you get it all done soon; be curious to see the results.

NEWTRON · 05-02-2023, 11:31 AM

Quote:

Originally Posted by scottygrape

So I ended up switching to b58 spark plugs and the issue is now fixed. So weird.

Did you swap out the boots on the b58 coils? I know that the n55 plugs are shorter and will leave an air gap with stock b58 coils that can cause arcing. Could be why the B58 plugs are not having issues.

scottygrape · 05-02-2023, 04:54 PM

Quote:

Originally Posted by NEWTRON

Did you swap out the boots on the b58 coils? I know that the n55 plugs are shorter and will leave an air gap with stock b58 coils that can cause arcing. Could be why the B58 plugs are not having issues.

Yes I did but good thought.

scottygrape · 05-02-2023, 04:55 PM

Quote:

Originally Posted by yupetc

Glad that's been addressed. Seems like you're having quite a handful on this build. Hope you get it all done soon; be curious to see the results.

Lol your telling me man. Trying to get it all sorted out and then I’ll wrap up the build thread with a ton of info

scottygrape · 05-05-2023, 05:34 PM

Update. It is now cracking b58 plugs. I have no idea what’s going on. Lol

5w20 · 05-05-2023, 07:03 PM

I'd go back to the stock ignition system. Seems like these engines have high failure rates with aftermarket ignition systems.

scottygrape · 05-05-2023, 07:11 PM

Quote:

Originally Posted by 5w20

I'd go back to the stock ignition system. Seems like these engines have high failure rates with aftermarket ignition systems.

I’ve NEVER heard of a complaint with b58 coils. They are as good as it gets.

5w20 · 05-05-2023, 07:47 PM

Quote:

Originally Posted by scottygrape

I’ve NEVER heard of a complaint with b58 coils. They are as good as it gets.

so you have a b58?

scottygrape · 05-06-2023, 05:41 AM

Quote:

Originally Posted by 5w20

so you have a b58?

I have a n55 with the Nexsys b58 coil kit

Jvac · 05-06-2023, 08:41 AM

Quote:

Originally Posted by scottygrape

I have a n55 with the Nexsys b58 coil kit

I would agree with this guy then- I'm not the authority around here but I can't recall reading about anyone else experiencing this issue with n55 parts even on aggressive tunes, nor do I recall anyone running the b58 coils. The next step would be to eliminate this variable and see if the problem persists

04-30-2023, 08:47 AM	#1
scottygrape Private First Class 101 Rep 107 Posts Drives: F30 335i Xdrive Join Date: Feb 2023 Location: Wisconsin iTrader: (0)	Need help with misfire and cracking plugs on new build Hello all, Been having a weird issue with my car. This is a completely new build. Built motor, pure 750, Dorch stage 2, lift kit, m5 eu5 injectors, Nexsys b58 coil kit, e85 flex fuel custom tune by Chris Kontos. We were in the process of going through revisions and all was well. We were at 27-28psi. I did a clean 4th gear pull. 5 minutes later did another pull and it started misfiring really bad under high load. Bunch of codes for Misc misfire. There is nothing weird in the logs. Fuel pressure and AFRs are perfect. Minimal timing corrections. Upon troubleshooting and investigation I have now cracked 4 different spark plug insulators on all different cylinders. I am using ngk 97506 gapped to .026”. I am torquing them properly with a swivel to ensure I am not cracking the insulators on install. Anyone have any advice? Here are some logs and pics. Here is a clean log https://datazap.me/u/scottygrape/cle...og=0&data=3-15 Here is a log of the misfire https://datazap.me/u/scottygrape/4th...og=0&data=3-15 Attached Images
	Appreciate 0 Tweet Quote

04-30-2023, 10:33 PM	#2
thejeremyman9 Major General 4392 Rep 7,634 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	Usually happens with counterfeit NGKs. Where did you buy them from? You could try some OEM plugs and gap down if needed.
	Appreciate 0 Quote

05-01-2023, 09:23 AM	#4
yupetc Captain 399 Rep 667 Posts Drives: 2015 X535i Join Date: Feb 2013 Location: Houston, TX iTrader: (0)	I've had similar issue where the porcelain base at the bottom came loose from the hex housing, causing misfires and random limp modes. Got real lucky because I couldn't find anything wrong with the car for few weeks then decided to start from the ground up by replacing parts which could be a suspect. On my first go was the sparkplugs and I realized I didn't pay attention to the sparkplug body before, always only looking at the ignition tip. So got real lucky to locate the loosened porcelain on the non-cylinder side of things. No more issues ever after. For cracked sparkplug housing, I've never personally dealt with, but back in the olden days where I've apprenticed under some Toyota MR2 guru's, there were cracking sparkplug issues on VERY high boost. I do not remember the numbers, but I vaguely recall that a combination of high boost, cylinder firing shockwave, can contribute to cracking it. This is over 20 years ago, so I couldn't go further remembering. Sub'd for more discoveries and a learning curve for myself. __________________ 2015 X535i - CP Piston, Manley Rod, ACL/King bearings, MILVs VRSF full charge Pipe, Wagner FMIC, Hybrid Turbo, MHD2+ VRSF DP, UR Front/Rear Sway Bars, Eibach springs, Bilstein B6 2015 MINI COOPER - Mahle Pistons, Max Rods, BMS intake, CTS charge pipe, Wagner Intercooler, ByteTronik Tune, VRSF DP 2017 540i - MHD2+, VRSF DP, TU Pump
	Appreciate 0 Quote

05-02-2023, 04:39 AM	#5
scottygrape Private First Class 101 Rep 107 Posts Drives: F30 335i Xdrive Join Date: Feb 2023 Location: Wisconsin iTrader: (0)	So I ended up switching to b58 spark plugs and the issue is now fixed. So weird.
	Appreciate 0 Quote

05-05-2023, 05:34 PM	#10
scottygrape Private First Class 101 Rep 107 Posts Drives: F30 335i Xdrive Join Date: Feb 2023 Location: Wisconsin iTrader: (0)	Update. It is now cracking b58 plugs. I have no idea what’s going on. Lol Attached Images
	Appreciate 0 Quote

05-05-2023, 07:03 PM	#11
5w20 @_sunbish 294 Rep 612 Posts Drives: Bmw 435i & 340i Join Date: Mar 2019 Location: Houston iTrader: (0)	I'd go back to the stock ignition system. Seems like these engines have high failure rates with aftermarket ignition systems. __________________ '14 435i RWD - BM3 stage 2+ E30/bolt ons/stock turbo/full drag pack -- [10.9@125].....60 to 130 - 8.5 '16 340i RWD - BM3 stage 2+ E50/bolt ons/stock turbo/full drag pack -- [10.2@131]......60 to 130 - 7.5
	Appreciate 0 Quote