[SWFLf10]

I was running the Nexsys B58 coil adapter kit on my N55 powered F10 for around 12,000 miles.

I had no issues until just the other day when I got a drivetrain malfunction and a very rough running engine while merging onto the highway.

I pulled off the highway and read the codes with the Foxwell scanner I keep in the car for instances such as this. The scanner showed a cylinder 4 misfire. I decided to limp the car home and look into the issue the next morning.

That next morning I started by pulling the ignition coil from cylinder 4. Immediately I noticed a crack and pinhole in the boot. There was a white residue around the pinhole where I assume the coil shorted to the spark plug well. Seeing this I decided to pull the rest of the coils and replace them with the OE Delphi coils I ran previously without issue.

After I pulled the coils, plug adapters, and aluminum adapter mounts, I looked closer at the boots I had removed. I noticed the ends had torn off and were now stuck on the spark plugs. So I decided I would have to pull the plugs to remove this excess rubber. I quickly realized that my spark plug socket wouldn’t go past the rubber and I had to attempt to remove the rubber with the plugs installed.

Three of the six rubber pieces came out in one price by pushing the socket down onto the rubber as far as I could then twisting and pulling slowly. The other three ended up shredding to pieces as I tried to remove them. It took an hour or two of me breaking the rubber apart with the socket and then vacuuming the pieces out with a shop vac with a smaller diameter rubber hose attached to reach down into the spark plug well. There was still some rubber stuck on these three plugs, but I was able to finally get the socket to grab the plugs. I removed them, the offending rubber, then reinstalled them.

I then installed the OE Delphi coils and flashed my DME with an updated bm3 flash to account for the change of coils. (I flashed it to allow the use of the Nexsys adapters and B58 coils previously). I was able to start the car and clear the codes without any further issues.

Let this be a warning that the boots supplied with the Nexsys kit seem to be inferior to the OE and OEM solutions and can potentially crack and cause misfires, dead coils, and can potentially become a real pain to remove later on down the line.

The issue with the rubber boots falling apart at the plug could potentially be addressed by using dielectric grease to help lubricate the rubber where it contacts the ceramic of the plug. The crack that I believe led to the short seems to be an issue regarding the length of the rubber boot. Every boot appeared to be bent in the middle, suggesting that they are slightly longer than they should be for this application.

TLDR: The Nexsys spark plug boots can potentially fail and cause a variety of issues.

[Unspec]

Pretty standard practice to use dielectric on the ceramic part of the spark plug IMO.

[SWFLf10]

Originally Posted by Unspec

Pretty standard practice to use dielectric on the ceramic part of the spark plug IMO.

I don’t recall if these boots from Nexsys had it preapplied or not. I could be wrong, but I believe all the coils I’ve bought from any brand for any BMW I’ve owned has had it preapplied.

I will add that their site does say to use dielectric grease on the boots, so I don’t believe they would come with any preapplied. I honestly can’t remember whether or not I applied any myself or not on these.

[Unspec]

Originally Posted by SWFLf10

I don’t recall if these boots from Nexsys had it preapplied or not. I could be wrong, but I believe all the coils I’ve bought from any brand for any BMW I’ve owned has had it preapplied.

I will add that their site does say to use dielectric grease on the boots, so I don’t believe they would come with any preapplied. I honestly can’t remember whether or not I applied any myself or not on these.

I know for a fact that delphi coils do not come with it pre-applied, as I had to apply it.

[SWFLf10]

Originally Posted by Unspec

I know for a fact that delphi coils do not come with it pre-applied, as I had to apply it.

I swear the last time I ordered a new set they had lines of grease already inside the boot. I very well could be mistaken, I may be thinking of another brand I’ve used in the past.

I still have never had an issues with other boots getting stuck previously. Maybe I got lucky?

And I’d still like to know if I somehow screwed up during the Nexsys install, or if their boots really are too long or if some other issue caused them all to bend and cause the tearing in the boot that led to my short.

[Unspec]

Has Nexsys responded at all?