N46 Coil Pack Lifting

[DarrylvanNiekerk]

Looking for some advice.

I have been battling with rough running and intermittent misfires on an e90 320i - N46.

After a lot of back and forth I have eventually identified it as the front coil pack lifting off of the spark plug and not making good contact.
The sparks are 22000km old as are the coil packs - NGK and Dekra respectively.

I have left the top engine cover off so I have constant access to the coil pack in order to confirm it is making good contact - see hovering I have to do before every trip now.

I can't figure out how to secure the coil pack so it can't lift, I think as the car heats and cools the coil lifts and sometimes there is a very noticeable gap when I press it back down.

I have tried cleaning the spark plug porcelain, cleaned the coil pack rubber, taped the coil pack rubber with fabric electrical tape and also tried to compress the rubber with heat shrink and nothing has worked.

I've tried searching for a solution online but the closest suggestion was finding a way to secure the pack in place but can't see anything I can use as an anchor point.

Any suggestions would be greatly appreciated.

 

[Spanky]

I would just replace honestly, not an expensive exercise.

 

[DarrylvanNiekerk]

I would just replace honestly, not an expensive exercise.

Sorry I got the brand wrong, they are Delphi coil packs.

What would potential issues be with mixing brands, like throwing a Bosch one in to replace the errant Delphi one?

Considering the spark has been messed around with this should I replace them at the same time

 

[Spanky]

Putting a Bosch in that location, while the others remain Delphi, is not going to be an issue if they're built to the same specification.

To determine where your interfacing issue lies, plug side or coil side, you could replace only the cheapest item of the two first and see whether you have resolved things. If not, replace the other too. You could also swap a pair of packs around and see whether the misfire moves with, then you know it's the pack and not the plug.

Personally, I like to replace those types of consumable components in batches (i.e. all coil packs together and all spark plugs together).
That said, it's not absolutely necessary, but it does give one a new datum and known-good reference point which is better practice IMO.

 

[DarrylvanNiekerk]

Putting a Bosch in that location, while the others remain Delphi, is not going to be an issue if they're built to the same specification.

To determine where your interfacing issue lies, plug side or coil side, you could replace only the cheapest item of the two first and see whether you have resolved things. If not, replace the other too. You could also swap a pair of packs around and see whether the misfire moves with, then you know it's the pack and not the plug.

Personally, I like to replace those types of consumable components in batches (i.e. all coil packs together and all spark plugs together).
That said, it's not absolutely necessary, but it does give one a new datum and known-good reference point which is better practice IMO.

Thank you very much.

I know it is the front coil pack because this is the only one that can be pushed back down and afterwards the idle is clean again.

As you say it's best to replace in sets but it is not the performance of the coil pack just the fact that it is lifting which I can't understand why.

If I may pick your brain quickly please:

Delphi coils bought from BMW on special cost R2600. Would Bosch be a better choice and where do you normally buy from?

I actually think I have Bosch plugs in.
I see you can get Platinum ones for not much more then standard copper ones, I can't see the Iridium being worth the extra cost.
What would be the best set of plugs to use on this car?
Full rebuild, slightly higher compression than normal, using 5W30, engine has around 25000km on it, aftermarket decat exhaust.

 

[Greenz]

Diesel electric stock bosch.

I'd probably swop the coilpack in question with another one just to be 100% sure it is indeed the problem.

 

[Spanky]

I know it is the front coil pack because this is the only one that can be pushed back down and afterwards the idle is clean again.

Okay, but does that specific coil pop up on other plug locations too? If so, you know its the coil itself. If not tested at other locations, you still don't know for sure which side of the interface (plug or coil) is the issue.

I'd say figure that out first before worrying about replacing bother sets of components (which wasn't implied, and is overkill).