[Korvo]

Greetings!

I'm hoping that someone can help me understand what's going on with my engine.

2014 N55 X-Drive
80k miles
MHD Tuned (Typically Stage 2 - 91 Octane)
High Flow Downpipe
Upgraded Intercooler
MPPK Air Box
Stock Plugs, Stock Gap
Dinan Exhaust

I've been fighting with high load misfires for over a year now. It's typically one cylinder and it can be solved by replacing the coil pack. The problem moves with the coil pack, so if I move the pack to a different cylinder, that cylinder becomes the problem. I was not having any issues until I decided to replace the coils and plugs as preventative maintenance over a year ago. Coils are Delphi and plugs are BMW OE (from FCP). I have replaced spark plugs twice in the past year. Today, while on my way to work, I punched it at 3k RPM in 2nd gear (6MT). It threw a code immediately and put me into limp mode. I can typically turn the car off and on to get it working again, but today the cylinder remained deactivated. Clearing codes in MHD didn't work either. I limped home and put all of the original coils back in - the spark plugs looked great. The car currently drives normally on MHD but I decided to flash back to MPPK until I get this issue sorted out. When I look in the end of the coils, I can see some black discoloration on the plug contact point. Not a ton, but not clean. None of my stock coils had this discoloration and every new coil looks the same. It also appears that there are small indents where the plug end touches the coil contact.

I'm wondering what could cause coils to fry like this… Heat from stock plugs? Bad batch of coils?

I've read through hundreds of posts over the year and can't find anything similar to what I'm experiencing. Any advice would be greatly appreciated. I'd like to get back to a reliable MHD Stage 2+ on 93.

[LA1Z24]

In auto diagnostics, when I car blows 1 coil pack consistently, it is usually because that cylinder is running lean. The fuel makes it easier for the spark to jump the gap. When the cylinder is lean, the coil has a harder time discharging, and smokes the coil pretty fast.

[yupetc]

Stage 2 should get you 400whp and a tad more, right? If so, I'd suggest you take a look at this video and see if buying a set of Eldor coils may help you resolve the issue:

I'm having very similar issues right now and I had just ordered mine, but I won't get to installing it until much later on, got some suspension work to resolve first. But will be definitely trying out the Eldor coils myself in due time.

[thejeremyman9]

Originally Posted by yupetc

Stage 2 should get you 400whp and a tad more, right? If so, I'd suggest you take a look at this video and see if buying a set of Eldor coils may help you resolve the issue:


I'm having very similar issues right now and I had just ordered mine, but I won't get to installing it until much later on, got some suspension work to resolve first. But will be definitely trying out the Eldor coils myself in due time.

Stage 2 MHD on 91 octane is pretty well under 400whp FYI, but that video is probably still a good reference for coils in general

[LA1Z24]

Originally Posted by yupetc

Stage 2 should get you 400whp and a tad more, right? If so, I'd suggest you take a look at this video and see if buying a set of Eldor coils may help you resolve the issue:

I'm having very similar issues right now and I had just ordered mine, but I won't get to installing it until much later on, got some suspension work to resolve first. But will be definitely trying out the Eldor coils myself in due time.

He has an issue in this cylinder. Another brand coil is not going to fix this. Maybe prolong the inevitable...But in the end he needs to find his issue. Either its a lean cylinder, or he needs to voltage drop test the coils to find the high resistance in the circuit.

[Korvo]

Thanks for the replies, everyone! To clarify, the issue moves around cylinders so it's not one specific cylinder that's problematic. I'll watch that video. I did not know that there were better coils available. Had I known, I would have gone with that!

[johnung]

Originally Posted by Korvo

Thanks for the replies, everyone! To clarify, the issue moves around cylinders so it's not one specific cylinder that's problematic. I'll watch that video. I did not know that there were better coils available. Had I known, I would have gone with that!

Last year I switched from stock coils to Eldors. Full E85. Runs great!