Spark Plugs and Misfire

[mister5kevin]

I have the N54 twinturbo inline 6 engine. I recently got a check engine light at 65k, it was a Misfire in cylinder 1. Does this sound like Im due for a spark plug change?? If so I have a couple of questions.

What is the prefered spark plugs? I know there are different types like platinum, Iridium, 4 tips, NGK, Bosch.. etc..

Also am I going to have to change all 6?

Let me know! Thanks!

[blbward]

i've had misfire in my 545i I change all eight spark plugs also coils.everything is ok now. it was my #1-5 & 8 no engine check light. best plugs to use is Bosch. try and see if any changes.

[thedohboy]

The N54's are notorious for a few problems: faulty injectors, high-pressure fuel pump, and bad turbos. Make sure you note all the symptoms.

I recently had a terrible series of misfires that led up to being stranded waiting for a tow. I had long starts, rough idle, gray/white smoke that smelled like fuel and 4 check engine lights spaced out over 9 days. After driving and warming the engine, the warning would clear and idle would smooth out. With 48k miles on my '08 535i, it's now out of warranty but i took it to the dealer nonetheless. In California, there's an extended fuel emissions warranty (7 year,70k miles) that covered the replacement of all 6 injectors (though only cylinders 1-3 were faulty) and spark plugs 1-3. I paid out of pocket for the extra 3 plugs.

I have read the newer plugs can last up to 100K miles. My SA would not tell me directly. He said I might need to change them at 50, but it's possible they'll last to 100K.

Anyway, to answer your questions, I would do all 6. You don't want to deal with another misfire in 10K miles when you can proactively deal with it now. FWIW, I like what BMW recommends, which I think BMW has switched to NGK.

[oldman12]

Terry at BMS recommends OEM plugs as he has tried others and they were not holding up to increased boost levels. With OEM's, you don't have to worry about gaping them either.

[mister5kevin]

I brought the OE Bosch. Will install later this week. Hopefully that solves the throttle hiccup problem

[mister5kevin]

Spark plugs all changed but stills throws a cylinder 1 misfire at hard revs. I already swapped cylinder 1 coil with another cylinder and still comes up as misfire in same cylinder. What should be my next replacement?

[centexE9x]

Originally Posted by mister5kevin

Spark plugs all changed but stills throws a cylinder 1 misfire at hard revs. I already swapped cylinder 1 coil with another cylinder and still comes up as misfire in same cylinder. What should be my next replacement?

Its tricky on n54s. If the misfire is fuel related( i.e. bad injector), the Cyl its faulting can not be trusted (only the bank). So if it faults Cyl 1 the fault could be on any bank 1 Cyl (1-3)

If its ignition related (bad coil) then the vehicle is acurate at the faulted cylinder. It's up to you do diag properly and find which it is (fuel vs ignition/mechanical)

My usual first step on any N54 diag is to pull all the plugs and look for signs of fuel fouling. If I don't see any then I usually move to coils. After that its time to check compression and physical problems. I've seen rockers fall off, and even then intake being coked up will cause this issue. So you have a full plate now lol

Stop replacing parts and diagnose it/fix it! : D

[mister5kevin]

After some research. I found this.

http://www.bmwblog.com/2010/10/27/bmw-to-conduct-voluntary-emissions-and-safety-recalls-n54-engine-130000-vehicles/

It was a recall on n54 fuel pumps. I will be calling them. Hopefully this may be a cause of the misfire.

[centexE9x]

Originally Posted by mister5kevin

After some research. I found this.

http://www.bmwblog.com/2010/10/27/bm...0000-vehicles/

It was a recall on n54 fuel pumps. I will be calling them. Hopefully this may be a cause of the misfire.

I hope that does it, but I've never seen a hdp pump cause a misfire. Mostly will just cause the car to throw faults and go into limp mode.

[PJinCA]

Originally Posted by centexE9x

I hope that does it, but I've never seen a hdp pump cause a misfire. Mostly will just cause the car to throw faults and go into limp mode.

The fuel pump itself won't cause a misfire, however, as others mentioned - when the HPFP fails it can take the injectors and fuel rail with it. Not to mention problems with the turbos

[centexE9x]

Originally Posted by PJinCA

The fuel pump itself won't cause a misfire, however, as others mentioned - when the HPFP fails it can take the injectors and fuel rail with it. Not to mention problems with the turbos

I just got thrown for a loop. You just lumped in turbos on a simple misfire? Lol. I see these all day everyday. 99% of the time it's one of 3 things. Injector, plug, coil. Next time I get a n54/n55/n63 powered car in my stall with a CEL. I need to get on the forums and ask advice!

HILARIOUS