[28inchrims]

evening folks (excuse me if this is the incorrect section to post) unfortunately im having an issue with an N55 motor that i changed spark plugs on. car is a 2015 335i.

so i changed the spark plugs and right away car got a drivetrain malfunction and has multiple misfires

i did some research and read incorrect torque can cause such an issue and with suspect of my torque wrench not being calibrated correctly i tried different one and to no success the misfires persisted.

i changed all the plugs back to the original old plugs (and double checked both sets were correct part numbers) and no change.

my question is what can be done now? ive cleaned out as much of the carbon deposits that were visible as per service bulletin on this particular diy indicated. i suspect maybe carbon fell into the cylinders? how can i get it out? i have access to a compressor and an x431 launch scanner so any help would be greatly appreciated

[thejeremyman9]

What do you mean you cleaned out carbon deposits? What service bulletin? Never heard of that.

What codes? Shadow or active? Specific cylinders?

Any logs?

Double check coils and all connections?

Did you crack the insulators during removal or install?

[28inchrims]

https://www.newtis.info/tisv2/a/en/f...plugs/Hp3ZNwmS

this bulletin ^^

" Deposits that are not removed according to instructions may enter the combustion chamber and lead to uncontrolled combustion. Remaining deposits in the area of the spark plug seal can lead to leaks and to the spark plugs coming loose during engine operation "

i blew them out with compressed air but i suspect some particles might have gone inside

i thought i might have cracked insulators thats why i put the original set back in but i can check that next. i did a visual inspection and they all looked solid

[F32Fleet]

Dielectric grease? It can cause the coil to walk off the plug and a misfire.

[28inchrims]

no grease or anti seize of any kind was used. just straight plug install like most suggested

[28inchrims]

i can say im mechanically inclined. ive done multiple valve cover gaskets oil filter housing gaskets water pumps etc im not new to it but this has me stumped forsure

[thejeremyman9]

Originally Posted by 28inchrims

https://www.newtis.info/tisv2/a/en/f...plugs/Hp3ZNwmS

this bulletin ^^

" Deposits that are not removed according to instructions may enter the combustion chamber and lead to uncontrolled combustion. Remaining deposits in the area of the spark plug seal can lead to leaks and to the spark plugs coming loose during engine operation "

i blew them out with compressed air but i suspect some particles might have gone inside

i thought i might have cracked insulators thats why i put the original set back in but i can check that next. i did a visual inspection and they all looked solid

You shouldn't have blown air into the wells after pulling the plugs. However i doubt a tiny amount of debris caused anything... You could inspect your cylinder walls with a boroscope if you want to. I would read this thread as it sounds like a similar issue. https://f30.bimmerpost.com/forums/sh...5#post26058125

Also you didnt respond to my other questions about codes, logs, etc. That would be particularly informative.

My initial guess would be something coil or re-install related, other than the plugs themselves. You really need to know if the misfires are on a specific cylinder or something so you can narrow this down.

[28inchrims]

im sorry no i blew air before pulling the plug as id seen on a few DIYs i watched before doing it

car has codes for multiple cylinder misfires, misfires on cylinder 3,5,6 and code for fuel shutoff on those same cylinders. are there any specific logs i should pull and post as ive never pulled logs before to show.

i did check coils and connections everything seems good

the plugs used were bosch ZR5TPP33 which i believed were pre gapped as i didnt play with any gapping. im reviewing the thread you posted right now as i type this

all the help is greatly appreciated thank you

[thejeremyman9]

Originally Posted by 28inchrims

im sorry no i blew air before pulling the plug as id seen on a few DIYs i watched before doing it

car has codes for multiple cylinder misfires, misfires on cylinder 3,5,6 and code for fuel shutoff on those same cylinders. are there any specific logs i should pull and post as ive never pulled logs before to show.

i did check coils and connections everything seems good

the plugs used were bosch ZR5TPP33 which i believed were pre gapped as i didnt play with any gapping. im reviewing the thread you posted right now as i type this

all the help is greatly appreciated thank you

If it occurs on specific cylinders you can try swapping the coils around to see if the problem follows the coils.

Did you at least check the gaps?

[Rebound]

Originally Posted by 28inchrims

im sorry no i blew air before pulling the plug as id seen on a few DIYs i watched before doing it

car has codes for multiple cylinder misfires, misfires on cylinder 3,5,6 and code for fuel shutoff on those same cylinders. are there any specific logs i should pull and post as ive never pulled logs before to show.

i did check coils and connections everything seems good

the plugs used were bosch ZR5TPP33 which i believed were pre gapped as i didnt play with any gapping. im reviewing the thread you posted right now as i type this

all the help is greatly appreciated thank you

I would swap coils 1,2,4 for 3,5,6

I guess that perhaps one coil (or coil connection) failure may cause multiple failures, but I'm not certain. I often worry that moving these coils trashes those thin wires; they're old and they've been subjected to tremendous heat over the years. Again, I'm not certain.

[F32Fleet]

I'm thinking a wiring issue. Contact this BMW master technician: https://bmwtechnician.com/

[28inchrims]

i finally had the chance to look over the car once more as i had other obligations to attend to

turns out the car indeed had two bad plugs (didnt look like they had any cracks on insulator but replacing them fixed it) and one that was overtightened. car is running smooth appreciate all the useful input

[thejeremyman9]

Originally Posted by 28inchrims

i finally had the chance to look over the car once more as i had other obligations to attend to

turns out the car indeed had two bad plugs (didnt look like they had any cracks on insulator but replacing them fixed it) and one that was overtightened. car is running smooth appreciate all the useful input

How do you think you damaged the plugs? I have been seeing a lot of similar posts recently and its making me a little paranoid to change mine.

Did you use a Ujoint when removing and torquing the plugs as the manual recommends? Or just a straight extension?

[28inchrims]

i had just used a straight extension which is probably how i damaged the plugs since they do go down into the motor at quite an angle.

i would definitely stick to the manual and use a u-joint next time around and an accurate torque wrench to avoid over tightening

[jh_f30]

Originally Posted by 28inchrims

i had just used a straight extension which is probably how i damaged the plugs since they do go down into the motor at quite an angle.

i would definitely stick to the manual and use a u-joint next time around and an accurate torque wrench to avoid over tightening

+1

When I do my plugs with a 3/8" torque wrench, low torque settings (ie. less than say 15-20ft-lbs) feels a little iffy. Next time around, I'm gonna invest in a 1/4" torque wrench that's set to in-lbs.

[thejeremyman9]

Originally Posted by jh_f30

+1

When I do my plugs with a 3/8" torque wrench, low torque settings (ie. less than say 15-20ft-lbs) feels a little iffy. Next time around, I'm gonna invest in a 1/4" torque wrench that's set to in-lbs.

I did a lot of torque wrench research and i ended up getting what i describe in this thread for the job:

https://f30.bimmerpost.com/forums/sh....php?t=1709198

Basically all the in-lb wrenches don't go high enough for plugs. I havent seen any that go up to 200 really... sucks because the torque spec is basically at the bottom of the 3/8 range or the top of a 1/4 range. That's why i got the electric device i mention in that thread to confirm.

[jh_f30]

Originally Posted by thejeremyman9

I did a lot of torque wrench research and i ended up getting what i describe in this thread for the job:

https://f30.bimmerpost.com/forums/sh....php?t=1709198

Basically all the in-lb wrenches don't go high enough for plugs. I havent seen any that go up to 200 really... sucks because the torque spec is basically at the bottom of the 3/8 range or the top of a 1/4 range. That's why i got the electric device i mention in that thread to confirm.

The HF one goes to 200 in-lbs. There are a couple on Amazon that go to 245/250 in-lbs.

Capri Tools 31007 20-245 Inch Pound Torque Wrench, 1/4-Inch Drive https://www.amazon.com/dp/B00PGIUK3I..._0-2SEbGP36BGJ


Capri Tools 31100 1/4-inch Drive Torque Wrench, 25-250 Inch Pounds, Diamond Ergonomic Grip https://www.amazon.com/dp/B01LZ51WEF..._-92SEb5XZY3Y7