[eeyang92]

Hey all,

I recently attended a track day and during the last lap in my session the car pulled power and went into limp mode. The engine was running rough, and when I got back to the pits I confirmed it was cylinder 3 continuously misfiring - the car had shut down cylinder 3.

I managed to limp home with 5 cylinders. I suspected it was my injectors since that was on my list of items to preventively replace. However, after I replaced all the EU6 injectors and performed the adaptation reset, my bimmerlink app was still reporting continuous misfires on cylinder 3. To note, I had replaced my spark plugs and coils only a few thousand miles ago as well.

Now I was sort of stumped, so I swapped my cylinder 3 coil onto cylinder 4. However, to my surprise, bimmerlink was reporting that cylinder 3 was continuously misfiring. I then swapped my spark plug over to another cylinder and cylinder 3 was still misfiring.

Given that I pretty much verified that my plug, coil and injector in cylinder 3 were all good (the usual suspects for misfiring), I'm not quite sure where the issue lies now. I do believe I smell gas on on the spark plug in cylinder 3 so it does seem the injectors are spraying but there is no spark? Does anyone have any ideas on what it could be?

I am running Stage 2+ MM (bootmod3) at 19 PSI with a Pure Stage 2 turbo (along with all the supporting mods - upgraded IC, inlet, radiator, DV, etc. basically FBO) and a E45 mix.

TIA!

[F87Tomei]

I had a misfire quite similar and the cause of that was because of my oil filter being damaged, causing a reduce in oil flow and caused improper valve timing.

Also another thing, but I doubt it is a worn cylinder. I am not a mechanic, but I just wanted to share my experience.

Hope all goes well 🙏🏻

[eeyang92]

Originally Posted by F87Tomei

I had a misfire quite similar and the cause of that was because of my oil filter being damaged, causing a reduce in oil flow and caused improper valve timing.

Also another thing, but I doubt it is a worn cylinder. I am not a mechanic, but I just wanted to share my experience.

Hope all goes well 🙏🏻

Hey, thanks for your input! That's pretty wild the oil filter would cause one specific cylinder to fail.

I'll go ahead and do an oil + filter change since I'm due soon anyways.

My only other suspicion at the moment would be perhaps the wiring hardness for cylinder 3 burnt out. I am running B58 coils which might have increased the load on the wiring harness.

[F87Tomei]

Originally Posted by eeyang92

Hey, thanks for your input! That's pretty wild the oil filter would cause one specific cylinder to fail.

I'll go ahead and do an oil + filter change since I'm due soon anyways.

My only other suspicion at the moment would be perhaps the wiring hardness for cylinder 3 burnt out. I am running B58 coils which might have increased the load on the wiring harness.

Now that I think about it, it was more than one cycliner misfiring. Sorry for the confusion it was years ago for me.

The wiring harness for both the coils and the injectors could be. Use a volt gauge and test the continuity.

[eeyang92]

Update:

I brought it to a local shop and it's not looking good. They sent me a video of a compression test on cylinder 3 and it's pulling 0 PSI, and when they smoke tested it, they said the smoke was pouring out of the intake, indicating the intake valve is stuck open.

So I'll need to get the head pulled and let them inspect the damage - so far they said their borescope confirmed the piston itself is fine, so I'm not quite sure what exactly happened to the valve.

As far as I know, I didn't money shift (they said they would have seen evidence of damage on the piston if it hit the valve) - the drivetrain malfunction popped up as I was powering out of a double-apex corner and the car suddenly starting misfiring and the injector shut down in cylinder 3.

Unfortunately, this is major $$$. Will update again when they finish disassembling the engine and find the root cause.

[eeyang92]

Update 2:

Turns out the piston was cracked and scored the cylinder walls quite severely. The shop was not able to find the chunks of missing piston (this may be relevant later in the update). The plan was to get Carbahn to machine and resleeve the walls but when they took their measurements, the damage was too deep for them to do in-house. The cost to send it to another machine shop would have been astronomical (almost the price of a brand new N55 engine, from what I've been told) so it was not worth it to fix the existing block.

I sourced a used block from a wrecked N55 M2 and had my shop put it in. I got the car back this week and everything felt great. However, when driving to work I noticed the oil temps steady increasing. Normally, in sport mode, the temp target is around 204F and it stays pegged there unless on a very long drive (where the ECU raises the temp for efficiency) or if I'm on the track and the cooling is being maxed out. Neither was the case on the drive to work, where I took it very easy and was cruising on the highway. The temps went to 230-235F, which was a bit concerning, but not yet catastrophic (I believe 250F would be very close to limp mode). When I slowed down on the local roads, it dropped to around 215-220F, which did seem to demonstrate to me the system was trying to target 204F, but had trouble doing so.

After parking the car, the radiator would also be running at full speed (I've never heard it so loud before) - this also was indicating to me that the coolant was probably pulling double duty trying to cool down the engine. One thing to note is the fan shroud wasn't 100% flush to the radiator (I will have the shop take a look at this), but I don't believe this would be the case of excessive oil temps and I had no indication of excessive coolant temps - coolant was around 100C (212F).

So at this point I was fairly stumped, so I dropped it off again at the shop. During my conversation with the SA, it occurred to me that if they never found the missing piston chunks (not in the pan), and there were no metal flakes in the oil, the chunks must still be somewhere in the system. The SA told me it is possible the piston chunk may have disintegrated, however if it disintegrated my feeling is that they would have found metal flakes in the oil filter (which they did not). I have a feeling this could explain why the oil temps are high - the chunk might be lodged in a oil line somewhere, impeding the flow of the engine oil. In retrospect, I should have had all the oil lines replaced while the engine was still out (I believe the shop reused as much as possible from my original engine minus the block itself).

My question is - is it possible for the piston chunk (assuming it cracked and fell down into the oil pain) to be picked up and put back into the oil lines? I would have thought there would have been a filter in the oil pickup in the pan to prevent this from happening? And if that was the case, they would have found the chunks in the oil pan. And if it really did get picked up, it should have been ran through the oil filter first (can someone confirm this?) before being send to the oil coolers, turbo, etc.

I will let the shop do their own investigation, however, assuming my reason above is sound, I am pretty much prepared to have them replace all the oil lines (and oil cooler). Would there be anything else that needs to be replaced? (Hopefully not the turbo!)

If anyone has any knowledge they can share on this, it would be much appreciated!

EDIT:

After giving it some thought - the oil thermostat technically doesn't open fully until 248F - thus any temperature issues around 200F should be in the domain of the coolant loop. I am leaning back towards it being a coolant issue, either there is something up with the water pump, radiator or even the fan shroud not being 100% flush with the CSF radiator (how important is this anyways?).

[-Eidos]

I'm sorry to hear this. On paper your setup should have been fine with the PS2 and OTS map at 19psi. Did you have any logs prior to blowing the motor? And do you run a flex fuel sensor?

[CalAcacian]

Originally Posted by eeyang92

Update 2:

Turns out the piston was cracked and scored the cylinder walls quite severely. The shop was not able to find the chunks of missing piston (this may be relevant later in the update). The plan was to get Carbahn to machine and resleeve the walls but when they took their measurements, the damage was too deep for them to do in-house. The cost to send it to another machine shop would have been astronomical (almost the price of a brand new N55 engine, from what I've been told) so it was not worth it to fix the existing block.

I sourced a used block from a wrecked N55 M2 and had my shop put it in. I got the car back this week and everything felt great. However, when driving to work I noticed the oil temps steady increasing. Normally, in sport mode, the temp target is around 204F and it stays pegged there unless on a very long drive (where the ECU raises the temp for efficiency) or if I'm on the track and the cooling is being maxed out. Neither was the case on the drive to work, where I took it very easy and was cruising on the highway. The temps went to 230-235F, which was a bit concerning, but not yet catastrophic (I believe 250F would be very close to limp mode). When I slowed down on the local roads, it dropped to around 215-220F, which did seem to demonstrate to me the system was trying to target 204F, but had trouble doing so.

After parking the car, the radiator would also be running at full speed (I've never heard it so loud before) - this also was indicating to me that the coolant was probably pulling double duty trying to cool down the engine. One thing to note is the fan shroud wasn't 100% flush to the radiator (I will have the shop take a look at this), but I don't believe this would be the case of excessive oil temps and I had no indication of excessive coolant temps - coolant was around 100C (212F).

So at this point I was fairly stumped, so I dropped it off again at the shop. During my conversation with the SA, it occurred to me that if they never found the missing piston chunks (not in the pan), and there were no metal flakes in the oil, the chunks must still be somewhere in the system. The SA told me it is possible the piston chunk may have disintegrated, however if it disintegrated my feeling is that they would have found metal flakes in the oil filter (which they did not). I have a feeling this could explain why the oil temps are high - the chunk might be lodged in a oil line somewhere, impeding the flow of the engine oil. In retrospect, I should have had all the oil lines replaced while the engine was still out (I believe the shop reused as much as possible from my original engine minus the block itself).

My question is - is it possible for the piston chunk (assuming it cracked and fell down into the oil pain) to be picked up and put back into the oil lines? I would have thought there would have been a filter in the oil pickup in the pan to prevent this from happening? And if that was the case, they would have found the chunks in the oil pan. And if it really did get picked up, it should have been ran through the oil filter first (can someone confirm this?) before being send to the oil coolers, turbo, etc.

I will let the shop do their own investigation, however, assuming my reason above is sound, I am pretty much prepared to have them replace all the oil lines (and oil cooler). Would there be anything else that needs to be replaced? (Hopefully not the turbo!)

If anyone has any knowledge they can share on this, it would be much appreciated!

EDIT:

After giving it some thought - the oil thermostat technically doesn't open fully until 248F - thus any temperature issues around 200F should be in the domain of the coolant loop. I am leaning back towards it being a coolant issue, either there is something up with the water pump, radiator or even the fan shroud not being 100% flush with the CSF radiator (how important is this anyways?).

Sorry to hear about the damage, that's everyone's nightmare.

The oil pan pickup does have its own filter, so any piece of the piston that dropped into the pan shouldn't be able to make it into the oil system unless it was extremely small.

[eeyang92]

Originally Posted by -Eidos

I'm sorry to hear this. On paper your setup should have been fine with the PS2 and OTS map at 19psi. Did you have any logs prior to blowing the motor? And do you run a flex fuel sensor?

Unfortunately, I did not log that run. Yes, I have flex fuel.

[eeyang92]

Originally Posted by CalAcacian

Sorry to hear about the damage, that's everyone's nightmare.

The oil pan pickup does have its own filter, so any piece of the piston that dropped into the pan shouldn't be able to make it into the oil system unless it was extremely small.

Good to hear about the filter! I also figured if there were metal shards in the system there would be catastrophic damage from oil blockage or worse.

The new engine is running smoothly, besides this coolant issue. I see that the computer is targeting 80C is Sport mode but on an easy cruise (local roads) the coolant temp will not drop below 100C. I see that the fan is at 90% and the water pump is 250 RPM (which I believe is the maximum RPM for our pumps). So this tells me that the ECU is desperately trying to cool down the system but is unable to.

I know the thermostat opens fully at 100C, so it is possible that below this temperature there is not enough flow to cool the system. But even at a stop light with the fan going and the pump going at maximum speed, the temperature will not drop below 100C.

I drained out 1 gallon of coolant and replaced it with distilled water, to rule out a possible error by the shop putting in too much coolant, but there was no change in behavior. The liquid that came out was clear blue, with no evidence of gelling.

I'm going to replace the radiator, thermostat and water pump as sort of a hail mary before bringing it in to the dealer to diagnose. I also have an endoscope to try to peek into as many hoses as I can.

Prior to this, the engine had no trouble keeping the coolant at 80C and the oil ~203F (the middle line). Now, on the highway, the oil will hover around 230F because the coolant is at 100C. While this is "technically" fine for road use, I'm pretty sure if the car can't handle a study-state highway cruise, it is highly probable it will overheat on the track.

Has anyone seen this before? My feeling the most obvious answer is that there is a blockage/restriction in the system... but so far I have seen no evidence of it.

[Renato Gambine]

Hey guys, talking about Brazil here!
Yesterday I had problems with my Precision Raceworks coils, the car ran normally... I stopped to change the spark plugs as soon as we finished the service, I went out for a spin with the car, unfortunately the M2 when it was going up to 5 thousand RPM or 6 thousand RPM it failed, I was disbelieved... I thought I was unlucky that the spark plugs were bad, it could happen.
To my surprise, it was the coils, as I returned the old spark plugs that still worked... and the car didn't return to normal.
I removed the coils and put in the OEM ones I have in storage and magically the car returned to normal. I don't understand, I put the precision raceworks in and it gives me a problem. Can someone help me!!???
My friend had the same problem.




Fala galera, falando do Brasil aqui!
Ontem tive problemas com as minhas bobinas da precision raceworks, carro funcionado normal... parei para efetuar a troca das velas assim que terminamos o serviço, saí para dar uma volta com o carro, infelizmente a M2 quando subia giro 5 mil RPM ou 6 mil RPM ela falhava, fiquei desacreditado... Achei que tive o azar das velas estarem ruim, pode acontecer.
Para minha surpresa eram as bobinas, pois retornei as velas antigas que funcionavam ainda... e o carro não voltou ao normal.
Tirei as bobinas e coloquei as OEM que tenho guardadas e magicamente o carro voltou ao normal. Estou sem entender, coloco as precision raceworks dá problema. Alguém pode me ajudar!!???
Meu amigo teve o mesmo problema.