Technical Strange - N54 29CD Misfire Cyl. 1

mspwerk

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Sep 9, 2022
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Hey guys…

I need some support from the N54 experts ;)

I moved to a custom tune on mhd and made some hard pulls/ logs to see whats going on…

Now my problem… At high rpm (something about 6300-6500) i always get some misfire 29CD at cylinder 1….

I changed directly almost everything…

- All 6 spark plugs (NGK ILZKBR7B8G - 0.5mm gap)
- All 6 Delphi Ignition Coils
- New Injector from BMW dealer on Cyl.1
(Index 12 like the other 5)

I tried the OTS Stage 2 and had no problem with that… On Stage 2+ i was able only on 5th gear at 6500 rpm (WOT) make the problem come back…

On the custom map i have the problem on 3/4/5 gear at 6300-6500 rpm (WOT)…

Its a full build racecar with a dct swap but that shouldn‘t matter at all…

I was thinking about the MOSFET stuff but i have a MSD81.

I also saw a guy put some teflon tape on the injector that would help that the injector do not rattle… But usually these problems are on cyl. 6

The compression of cyl. 1 is 8bar while starting car without ignition… and the compression is not going away after stopping to crank the engine…

I‘m a bit confused. Could it really be a problem on the head? Valves? Head Gasket? Piston rings? Or some other stuff? Or is it a electric problem? I don‘t know where to continue to search for the error.
 

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Catalin335xi

Lurker
Jun 29, 2023
20
6
0
Romania
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E92 335xi N54, built engine
Cyl1 is 8 bar but what about the others? Just wondering if it's out of line. I am guessing that the engine is either built or refurbished recently so carbon deposits should not be an issue...?
 

mspwerk

Private
Sep 9, 2022
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I checked cylinder 2 and it was 7.5bar…

Maybe i will check the others but i guess they might be close to that number…
A new engine is having something about 12-14bar i guess…

I‘m concerned about the sealing surface of cylinder 1 at the head…

For me it looks like fuel/ oil is around that area…

Video

The Intake/ Valves are clean… It was blasted not more than 5.000km ago…
 

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Catalin335xi

Lurker
Jun 29, 2023
20
6
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Romania
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E92 335xi N54, built engine
is there any oil in the spark plug hole? that could be from the valve cover or if you spilled over when topping up oil (ask me how I know).

If you are suggesting lost compression into the cylinder head easiest thing to do to check that is to run the engine with the oil fill cap open, you should feel if any air is coming out. If no air comes out you are all good.

Another thing that comes to mind is to check if the pins from the coil #1 harness are looking ok and that the ground cable of that coil does not have corrosion or anything else.

Also, not entirely sure if you mentioned, but do you have black soot on the injector (upwards of the seal, downwards is normal) ? Basically asking if you have any blowby.

P.S. We might have the exact same issue, I have a built engine too, and a misfire on cyl 5 only on high boost maps and only at high rpm over 6k, have good compression, swapped coils plugs injectors etc, then in desperation got new sets of coils/plugs/injectors and it fixed nothing....... In the process of finding a solution I found a shit-ton of things to check but none of them were my issue. Maybe one of them is yours tho. That's why I suggested the above.
 

mspwerk

Private
Sep 9, 2022
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The sealing of the valve cover is good…
Just down at the sealing area of the spark plug there is some fluid.

I forgot to mention and show that there are some grey colored markings on the ignition coil…

If i produce some misfire after few pulls than the grey marks are getting bigger… More misfire… bigger marks on the coil…

You can see the marks on the new coil and the old one…

I will try to mill the surface sealing area of the spark plug with the tool at the picture that i attached. The problem is… There is no tool with M12x1.25…

I will try to build my own tool with other different tools…
 

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Catalin335xi

Lurker
Jun 29, 2023
20
6
0
Romania
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E92 335xi N54, built engine
I have the exact same coils as you but when I pull out mine they always leave that black rubber boot behind and it's always a pain to fish it out.

As for the marks, I haven't seen that before, I will check on my car too. It might be a sign of it rubbing against the wall but I cannot see how it would be able to move in there. Maybe you are missing or have a damaged spark plug hole metal sleeve.

This one (part number 11127575422) :
sleeve.jpg
 
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mspwerk

Private
Sep 9, 2022
25
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0
I have the exact same coils as you but when I pull out mine they always leave that black rubber boot behind and it's always a pain to fish it out.

As for the marks, I haven't seen that before, I will check on my car too. It might be a sign of it rubbing against the wall but I cannot see how it would be able to move in there. Maybe you are missing or have a damaged spark plug hole metal sleeve.

This one (part number 11127575422) :
View attachment 83520
I throw them away…

The problem was also/ already there with the old coils/ ign. spark and the metal sleeve…

Dont see a necessary of this metal shield…
 

Catalin335xi

Lurker
Jun 29, 2023
20
6
0
Romania
Ride
E92 335xi N54, built engine
I throw them away…

The problem was also/ already there with the old coils/ ign. spark and the metal sleeve…

Dont see a necessary of this metal shield…
ah okay, if you had the issue before no need then. was trying to figure if it caused your coil to move around and thus make those marks
 

mspwerk

Private
Sep 9, 2022
25
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ah okay, if you had the issue before no need then. was trying to figure if it caused your coil to move around and thus make those marks
It shouldnt move because its sitting very damn tight in the spark plug and on the top… quit hard to get out the ign. coil sometimes 😄

Im also using delectric grease on the coil/ spark plug…
 

mspwerk

Private
Sep 9, 2022
25
4
0
The sealing of the valve cover is good…
Just down at the sealing area of the spark plug there is some fluid.

I forgot to mention and show that there are some grey colored markings on the ignition coil…

If i produce some misfire after few pulls than the grey marks are getting bigger… More misfire… bigger marks on the coil…

You can see the marks on the new coil and the old one…

I will try to mill the surface sealing area of the spark plug with the tool at the picture that i attached. The problem is… There is no tool with M12x1.25…

I will try to build my own tool with other different tools…

Just a short feedback...

I mill cut the surface area of the spark plug... It looks nice and clean... Like from the factory...
But at the end of the day it didnt help... Same problem...

I don't know but feels like it has something to do with valves/ valve springs/ knocking sensor...

Maybe the valves or springs can't handle the high rpm with the boost... Maybe there is a kind of frequency that the valves/ valve springs start to swing?

Another option is that my dct swap could really be important for searching the error...

There might be a difference from INA0S DCT to my IJE0S Manual BIN because of different knocking/ misifire configuratiuon...!?
Anyone know the difference?
 

boost135

New Member
Jun 20, 2017
6
0
0
Ride
bmw 135i N54
Having similar issue on cylinder 1, single turbo with custom tune, did you get to the bottom of it? mine does misfires on 15psi but on 23 psi there is no issue.