Findings and conclutions about misfires and ignition pulls

[135boost]

Hi

I started this cause there seems to be numerous different approach about this stupid and very annoying issue of n54 misfires

I think half of those is just related to worn out parts like stock coil, plugs, faulty injector or just clogged intake runner, piston ring land, or something else very obvious.
But then there seems to be a bunch of misfire issues not covered by those common easy fix and owners has throwed and swapped every part in whole engine department and still struggle with this issue.

First this engine is still just a petrol burner, air, fuel, squeez, bang, exhaust dump..
I have struggled with these for few years now and still miss the root cause for them. Trebila has been awesome help and p33p33 even more awesome help to tune this but still there is to much on the dark side of this issue, and for sure, i'm not the only one with this. This seems to be stupidly sensitive to all what can cause misfires.

At the end of day, solutions should not be in a level of "edge where maybe it ignite every pulse", more like enough room for to be sure we aren't even close to misfires, damn, gtr's with these miniatyre plugs iginite even with 55psi and 2000 horsepower and propably 40% more cylinder pressure at the moment of ignition without issues.

What i have read from these forums, numerous injector swaps, numerous playing with different coil packs, spark gap, finetuning of software, different plugs, wichcraft, gremlings, different brand of fuels etc and still misfires even with big players like Tony @ vtt, Terry @ burgertuning and numerous others too.

Damn it, even 1970 made carburator engine turbocharged ignite mixture without issues so why is this so damn difficult.

First known real issue, miniatyre size spark plugs what for sure is more prone to run to issues cause of very thin layer of insulator and frame been close to electrode, that is somethinw what just is, caused on limited space in combustion chamber in di engines.

Then few things about di and plug relation what can trig issues, injector is very close to spark plug and with very high horsepower n54, on di, when injection window start (not sure about excact timing cause of missing map in xdf but some guess is that window is some 250 degree ) piston is close to tdc and maybe there is on big injection quantitys in that situation to some degree of risk to wet the plug.

First question, have there been any notices of difference in full di to the max with bigger di hfpf systems versus di plus pi cause on that occation, di plus pi should be less prone to this if that is the case

Second question, b58 style spark plug with much more protected center electrode could also provide some protection against that wet foul possibilities, some notices if that does any positive effect against misfires. Someone maybe even tryed pi only?

Seems that pr coils, b58 coils etc has for sure enough energy to ignite this kind of combustion so i think we all can be sure it's nothing to do with pure spark energy. Energy need is also reduced with spark gap reducing even if combustion pressure increase energy need and spark resistance at level of 1 to 1

What about mosfets or cabling to coils, i don't think cabling are too small to proper support coil charge even if they ain't ment to support more than stock coils but what about mosfets ability to disspatch heat with much longer dwell times in optimated dwell maps? I really think we have enough knowledge on those proper optimum coil dwell tables to rule out thatwrong chargetimes from issue causings list.

There has been one test what i have found from web where those was measured and conclution was that b58 coil is superior to allmost everything what can be throwed in in dumb coil markets. Has there been any taughts on temperature issue or is there real differences when used smart r8 coils on misfire front?

What about heat sink glued with thermal glue on top of all mosfets? Not so very difficult task to do.

On mechanical side there has been reported that some teflon tape wrap to injector has cured a small amount of misfire issues, sounds like bush fix, it may work but not caused of better sealing to combustion, it should worse out that sealing situation caused by many time bigger area to be sealed than that orginal 8mm but there is one thing what on my opinion has been totally missed and what that teflon tape could on short term cure.

What if the issue on that is not gas leakage, but jiggering of whole injector as a result of combustion chamber high pressure pulses?

Seems to be that issue is escalating with boost pressures over 25 psi and that teflon wrap fix has been when there has been complains about injector bore been out of shape or loose.

I came to stupid taught, what if that big cylinder pressure is starting to resonate the whole injector against the injector holding clip, that could easily explain wear out injector hole, that for sure could cause very erratic injector behavings caused on movements inside of injector and it's needle. Area of injector is in size of 0.5cm2 (8mm cross section ) at injector injecton nose where that teflon seal sits so if there is some 100bar cylinder pressure at highest point, the spring has to be hold some 50kg force and i'm sure it does not withstand that without some warping or small resonation. What if the injector locking spring is orginally designed to work as some kind of hydrolock protector to give up after example double orginal cylinder pressure and designed to protect pistons and stock rods in a case of injector fairlure and pump combustion chamber full of gasoline? And then when we reach that level with double absolute charge pressure, what is in a level of prox 40psi compared to stock some 20psi abs, 14,7psi plus some 7 or 8 psi boost? Just playing with idea...like valve float, difficult to show out as small amount until it's sewere issue an can be heard.

On these n54, that resonating frequency is in a rateof 2500 to 4000hz, half of engine rpm so monitoring should on my opinion be done with high speed videocamera in a dyno under full pulls to se if there is a issue. That spring type injector holder is not to be seen in any diesels, tfsi, n55, b58 or other engine models so what if this is the real issue in these n54's and was at the beginning a idea of bmw engineers to do it as that mentioned protector cause it was their first di engine?
I think movement level to mesh up injector is in a level of 1mm or something so movement does not have to be even visible to eye without slow motion diagnostic video.

Easy fix for sure is stack 2 springs to clamp that injectors, doubling it's clamping force. Has anyone even tryed that?
I have a spare of those and for sure will throw them in to do road test to it but i don't have easy access to chassis dyno or high speed camera equipments to do real investigatios other than road tests.

On afr side to solve this issue, it seems to be regardless of afr, for sure very rich mixture is causing misfires but even of correct best power level afr or little on lean side of it, it seems to be a issue still having mystery misfires.

Next question, if that is dme related, then all with syvecs s6 or s7 should be without any misfire issue at all, is that the situation? If it is, then dig again us in to dme mosfets.

In some occations, there seems to be claims that weak battery is causing these kind of issues but
That should stress more generator than trig misfires if dme feed voltage stays on decent level.

For sure i know this is a network of different bus in these so maybe there is some relations caused of some mystery module like lfpf but i think it's long shot.


My setup starts to run to misfires in a region of prox 23-25 psi, tested 3 different injector packs, 3 different coil packs, both pr and n58 coil packs, slight different afr's, diferent plug gaps, different dwell table values, even p33p33 knowledge, and misfire is popping up somewhere in 6000-7100rpm at every pull with at least one gear recovered after second or two to normal again and to the point of misfire everything seems to be totally normal except ignition pulls
Propably related to some torque limit table, 6at (testing at the moment on 29psi and target at the end is 33psi with 1:1 boost exhaust pressure) what i think is a totally other issue.

That ignition pulls has been reported that is more prone on xi models, and if so, it can be related to noise from dront diff ve rwd cars, more than diferent in calibrations or something else, faulty prop shaft or half shafts can bring noise to oil pan what can trig it but on mine, i tested few pulls with knock deactivated at over 3500rpm and still puls so it's not knock in my situation.

Known trigger increaser is forged internals, check, high lift cams, check, closed deck, check, xi, check, so i have them all.


Taughts?, suggestions to keep my mouth shot? Ideas ? And yes, again, i know my english is not perfect so gramma lections suggestions don't belong here eather or could it be better to write on my natives Finnish or Swedish

 

[135boost]

so, first tests done, springs did not solve that misfire issue so we are from that point of view at starting point, but now at least that has been tested.

spring preload is at least close enough in stock springs, not sure how much there is room in those spring rates but it`s
tested only at 28 psi.

will continue with next tests..

 

[135boost]

One day more with stupid misfire issue again spent.
what if assumes continue, where to dig next, how to pinpoint root cause of this.
i`m not sure if there is any thing combine issues with ignition pulls and misfires but few notices

seems that at least ijeos xi start to get ignition pulls with load levels over 170 and tested all ready
-misfire deactivation
-knock module deactivation
-traction control deactivation
-different coils (stock, pr, b58)
-different plugs included b58
-injector spring load increase

in my setup that ignition pull start at 4000rpm and at prox 170 load.
there is over 170 load at lover rpm but no pulls.
i assume it`s something to do with calc torque cause of my big turbos i have issue to
brakeboost on line without plaing with ignition advance ant there is one hint where to maybe start
find solution to pulls.

it`s obvious not only rpm or load what trig it, i have pulled my timing with load 110-170 values to 4 degree after tdc
to 4000rpm and thed draw it to 10 degree btdc.
in mhd logs torque lim act is all time 0 so there is not to be found any clue of that.
at the beginning i had that torque lim act trigged but P33P33 solved that out to me.
he did huge help to mee sorting out and clarifying different tables and how they act and to write
bins to me pointing out right direction but now i`m stucked with these 2 issues

that ignition pull start at the moment my ignition start to advance so 170 with 4 degree atdc, no issue, and 4 degree btdc huge pulls, calculation vice there should be some prox 10% torque increase only.
what is difference between those 2 situations is on my opinion only calculations of torque and spreading that information to transmission and maybe 4x4 transcase module, what else can be hidden in that advance difference.

what i had figured up to date is that there is some torque related hidden features
what propably is different in ijeos xi than non xi but no knowing if that is related to trans, abs, xi module,
or what it ever could be.

is there possibility to dig out to xdf similair deactivation of all torque related modules,
separate different torque limit activation and
is there maybe more hidden features and tables involved to that ignition pulls and is there maybe that connection in pulls and misfires.

i will post few logs here with those pulls just to show how it looks like in my tune

 

[carabuser]

You should post a log.

Are the timing pulls corrections or just timing reductions without corrections?

 

[135boost]

No time at the moment but I can point you to a good starting place.

Page 648 of the BMW FR details the creation of the SOI and EOI parameters
Page 2122 of the Continental FR details how those signals are corrected

Chapter 7 of the Continental FR gives you a complete overview of the injection process.

I think the injectors work in 3 pulses so it's not as simple as just having a SOI and EOI setting. There's a distribution factor that's used to determine how much of the total fuel mass is injected at each pulse.

I've only looked at the tables that are different between ROM versions. The distribution factors change on the INA0S "is" tunes.

You are absolut right, sitting here reading that continental FR and on 2272 forward there is explained that ecu determine if second pulse is needed and after that if third is needed so there is 1,2 or 3 pulses depending on complex
combustion process evaluating, and everything not to be so easy, determination of different energy levels of each pulses. that happend in all three combustion modes, homo, strat and homo+strat.

i assume this is working much like cdi diesels with multiple injection phases but on diesels there is first very tiny combustion ignition phase and when mixture ignite, then there is main power injector stroke phase and maybe one or 2 burning control phases, first is to soften at least low rpm di diesel rattling but when rpm and load rises it start to move to one phase mode.

that could be interested to know if this is too switch over to one phase and in what kind of conditions.
misfires can be triggered from those conditions too, some treshold value overshooted, injector depend, when determination of swithcover is done.

ps, don`t know what shit that Frank Tetterborn has smoked but it must be very damn god one.. he should be the guy opening logic behind this ecu

pps i assume LC_TQI_P_MAX_INH_AS is trans and traction control depend and should be possible to flagout just in case to test if there is some hidden torque reducing requests

 

[Jeffman]

@135boost , thanks for starting this very thought-provoking discussion. I just read all of the comments and I’m wondering about the influence of the type of fuel on timing pulls and misfires. I have Motive FlexFuel installed, and it’s been my experience that with my setup (xi 6HP AT, N54 IJEOS, FBO, DI only, MHD V9 FlexFuel, 20 psi, stock turbos, PR coils) I’ll get several timing 3*-5* corrections on several cylinders above 5000 rpm using US 93 octane gasoline (10% ethanol). Interestingly, adding ethanol to the fuel to provide at least E20 eliminates most of the timing corrections (knocking), everything else being equal along with the FlexFuel tune adjusting AFR, timing and load higher a bit. I believe the current theory is that ethanol burns colder than gasoline so it helps to reduce combustion temperatures, and hence knocking.
In this regard, have you considered fuel type?

Also, in connection with E85 as a fuel, there is a recent posting on this forum that because E85 burns colder than gasoline, one should avoid using two-step colder plugs as ethanol requires a hotter temperature with spark to ignite. I find this very interesting.

Also, regarding the xi transmission effect, I believe the extra timing pulls on xi cars may arise, in part, from worn engine mounts (especially the right one near the hot exhaust) causing the engine to be out of alignment with the transmission. I believe such timing corrections may be influenced by the AT torque tables. I just replaced my engine mounts and am currently testing. I can also run xDelete to effectively disconnect the transfer case from the front diff and will experiment with that, too.

Good luck!

 

[135boost]

@135boost , thanks for starting this very thought-provoking discussion. I just read all of the comments and I’m wondering about the influence of the type of fuel on timing pulls and misfires. I have Motive FlexFuel installed, and it’s been my experience that with my setup (xi 6HP AT, N54 IJEOS, FBO, DI only, MHD V9 FlexFuel, 20 psi, stock turbos, PR coils) I’ll get several timing 3*-5* corrections on several cylinders above 5000 rpm using US 93 octane gasoline (10% ethanol). Interestingly, adding ethanol to the fuel to provide at least E20 eliminates most of the timing corrections (knocking), everything else being equal along with the FlexFuel tune adjusting AFR, timing and load higher a bit. I believe the current theory is that ethanol burns colder than gasoline so it helps to reduce combustion temperatures, and hence knocking.
In this regard, have you considered fuel type?

Also, in connection with E85 as a fuel, there is a recent posting on this forum that because E85 burns colder than gasoline, one should avoid using two-step colder plugs as ethanol requires a hotter temperature with spark to ignite. I find this very interesting.

Also, regarding the xi transmission effect, I believe the extra timing pulls on xi cars may arise, in part, from worn engine mounts (especially the right one near the hot exhaust) causing the engine to be out of alignment with the transmission. I believe such timing corrections may be influenced by the AT torque tables. I just replaced my engine mounts and am currently testing. I can also run xDelete to effectively disconnect the transfer case from the front diff and will experiment with that, too.

Good luck!

Hi

As fuel, this has been full e85 burning werchile for 3 year and as logged, ethanol content vary a bit but is in a window of 76-83 here.

Some toughts about mechanical side of plugs and their heat range, there should be temperature window where engine operates in those to prevent foul and overheat issues.
If the plugs hasissue to be too cold, they start to build up deposit because they did not reach plug " self cleaning " temp and at most it's obvious a issue occuring during cold starts and cruising at low load.

That temperature on my knowledge is in a range from some 250c-600c in very hot to maybe 450c-900c in very cold plug and just hit the window where engine operates, there is maybe small benefits from step to colder or hotter but if circumstances hit the window, there should not be issues on plugs in this proportions what we have with misfires and ign pulls.

In a wot situations, i'm sure that even with e85 these engines reach that center electrode temps.

My opinion is that if plug is way too cold, it allways foul from debris buildup and at first when load increase, it's cleaned and start to act right until circumstances where there is too much debris to prevent cleaning process to happend and that electrode ceaning process fail.

In my case, no issues whatsoever in cold starts, cruising or any other cold low load situations.

When used too hot plugs, we all know what happend so nothing new to write, melting electrodes, melted metal parts hitting turbines and pistons what for sure is no no...

 

[135boost]

Here is one log where misfire and knock modules are deactivated at over 3500 rpm

 

[carabuser]

Can you upload to datazap or use the built-in spoolstreet log tool.

 

[135boost]

datazap.me | Maantec | Log 1631447000

datazap.me

There is to be seen both issues, first on long way ign pulls, then misfire

 

[carabuser]

One thing that stands out is the rail pressure. It's pegged at the maximum sensor value, I can't see that being helpful at all.

 

[135boost]

I had issues with resonance in rail pressure and only solution to cure it was just to raise rail pressure to these levels.
I have twin hfpf in use (vargas double barrell solution ) with aem controller, i assum thatis a reason for those stupidly high hfpf values.

I'm in a level where double hfpf is not enough to feed the engine and i use as additional fueling 1200cc 100%dc external injector to feed this.

It started to run out of fuel at prox 6000rpm with stft maxed out and started to loose hfpf lone pressure.

That was one reason to dig out soi and eoi of injectors to find out if there could be left any more juice but then realized that it's combined hfpf pump capacity and injector size issue so i think i'm past stock di and some 230% over stock hfpf capacity at the moment.

With that max hfpf, fuel scalars at 2.00, and that additional prox 1200cc injector i could archieve in my calculations boost levels to 32-33psi @7600-7800rpm with this fueling system and with that quantity of fuel, it should archieve some degree of pull if those damn misfires and ignition pulls stays out of the way.


That's all juice i can get out..

 

[MR-KRAKA]

Good conversation here. I've had my struggles with XI/IJ as well mostly with getting repeatable good post shift timing it can be very frustrating and time consuming. Every now and then I'll get a bug up my ass and I'll go in Winols and define some random address after reading the disassembly for 30th time that I suspect could be the golden ticket for these and so far just disappointment. Does anyone know if IKM0S supports xi? I've never tried it but it would be interesting to see a troubled IJ tune ported to IK and seeing the results just a thought...

Anyways are you injecting E85 or meth with a single 1200cc injector? I assume you mean you have port injection running 6x 200cc injectors. I don't want to state the obvious since you seem to be very capable but boost is running over target from 5k+ and throttle closures with that much fuel being injected into the charge pipe is no good. besides that here's a few things to look at...

I'm sure you've already tried reducing reported torque? There's no need for it to be that high. Line pressures are maxed with anything over 600nm reported. assuming you're Auto.

I would try the recommended VCV settings for the HPFP again to get that pressure down and give it some time to adapt. You should have enough fuel there unless there's other issues. Define "crashing" anything over 1500psi I would call acceptable. Injectors correctly coded?

I'm not sure if I read right but you are intentionally running timing that low? This may be causing it's own issue on full E85 and you should continue the ramp to at least 10+ deg up top (with knock detection enabled of course)

It may be time to think about a 4 bar sensor to get you into a lower load range but there's always other knobs to turn on that front if not.

You should also free up some logging channels by getting rid of the 1-6 timing corrections and load interpolation. No need to have that and all cylinder timing logged. It would help to see LPFP, IAT, Boost mean, Load request, fuel mode, Maf etc. Trims are going to zero in your trouble area and no way to confirm what's happening (misfire I assume) If you post your bin file I could check it out. Looks like you have a lot going on there...

 

[135boost]

Thank you from this post, it's allways good to get other opinions to solve out things, moreofen solution can sit just in front of your nose.
First, that log with all 6 timing and correction was just to show the problem is not single cylinder pull, more of that it's quite
Similair trough all 6.



Normally i log at most those channels you was suggestion of.


Then case of that additionl injector, it's a single 1200cc but that does not seems to make difference cause these issues is with or without activating it, it was just a fix to running very high stft in rpm range over 6200rpm and when activated, there is not even to be seen in afr so other vice than fuel distribution concern, it work well enough.

About injector coding, they are right, checked and doublechecked on every injector swap it.

I finetuned little that boost not to overshoot but to be close as possible to target, so let's see if that solve something.

There is much p33p33 helped me to understand in these parameters, logic and how they affect each other, i'm very thankful about his help on these.

Irritating in these is that mess of tables and just to figure out that there is more and more hidden ones doing corrections and adaptions to the tune without you being able to know.

Then that 4bar map idea, that didn't even came to my mind, obvious, it could solve something in these cause it give a possibility to reduce load targets from over 200 to levels of 170-180 because it seems that issues start in all of us in load levels over 170 that for sure is to be tested. Do you have bosch part number for that 4bar tmap?
I assume you are using that 4bar tmap?, what all tables come in mind what has to be tweaked when changing over from 3.5 to 4bar?
One thing came to my mind too, about chargepipe pressure sensor, does that to be changed too in case of this 4bar tmap?

About fuel pressure, i try to reduce it by little amount not to hit that max value and still keep it from resonance, that resonance is propably fom aic keeping higher demand than dme controlled and then dme contolled just try to adjust the pressure to meet it's own target.

About ignition timing, under 4500rpm a have done in prox 12 cells "automatic antilag" to get boost up because of just size of these turbos. Timing is coming back to normal advance 4500rpm upwards,
Those timing pulls in specified cells is starting from 1800rpm at load of 100-110 and end in 4500 at 170.
I have similair tweaks in vanos tables too just to maximize boost ramping.
Without those, and with these size turbos you get 6-8psi at 4000rpm and numerous tests later tweaking cell after cell i now have that 8psi@2600rpm and getting 22psi @4000.
Those tweaks are very sensitible to changes, noticed that in some cells, 2 degree timing change made 5psi difference in pressure values so they just can't be copied, every one must search for their own sweet spots.

I will put a picture of my ign main and spool tables, just to open ideas of it, for gods sake, don't copy them cause it seems to be most case sensitive tables i had modified at least in case of this size turbos.

Beeing involved on these n54 for some 5 years, not to blame anyone, my opinion is that 80% of cures what is to be found from internet is based on pure wichcraft without any logic behind it, just "it worked to me, it is what it is "etc. And my opinion is that there in ot such thing as " it just work"
there just is reasons, logic, consequences, behind every issue and i'm more after root causes to figure out issues and solutions than just wichcraft level "test it" and no technical explanation why it could work.

Thank you very much of these responces and throwing new logical ideas in this conversation to all.
This conversation was started as much to dig out root causes to these issues as to dig out solution to my issues.
There is hidden features and wierd limits inside these dme's and maybe features in ikmos solve ijeos issues or maybe it just solve something and escalate a new ones.

To resolve issues, there is neded guys with skills to sort out those damos files, FR files, tehnical guys to know things about mechanical limitations and burn processes so it's not a easy task to anyone.
To figure out scale in these dme's, just open that FR and see that from BMW ans siemens, there was involved maybe 300 to 500 people doing this with factory support.

 

[135boost]

One day testing again and conclutions.

Misfire issue seems to be someway connected in my case to cylinder 6 somehow and it's not injector, swapped over that now 3 times, not coil, tested with both pr and b58, not plug, tested with too many different plugs, tested with some different plug gaps.

Like we all know, issues in misfires continues in this platform until that root cause is to be found, and resonance at least is not the case, even if i think that spring should be assembled in every one with over 700hp


Like
Now next speculations, if the misfire orgin is in dme, maybe those mosfets, what about current feed to mosfets or or temperature inside mosfets it selves?

Measure surface temp in outside of mosfets..

 

[iminhell1]

Are you testing with or without engine cover?
With cover, #6 gets the most heat. It still does with out the cover also but the little extra airflow seems to matter.

 

[135boost]

it`s without cover and cover does not affect mosfets for sure.
i`ll got eoi and soi maps and it`s not to do with them cause they are quite constant on those rew values, soi just seems at most to follow exhaust valve vanos tables just not to inject fuel to open exhaust channel and limits on eoi is limited to close spark. I did some 15 degree timing advance change on those and i will do some tests on that if it affect that misfire.

It can have some influence cause first i stretched that soi by 5 degree and got misfires in both banks instead in only second

 

[135boost]

Search continue, misfire issue is not triggered by injection window and single phase injection does not work as expected.
I did to be sure measurement of cylinder pressures with digital pressure meter and

Cyl 1 9.05
Cyl 2 9.15
Cyl 3 9.45
Cyl 4 9.25
Cyl 5 9.20
Cyl 6 9.40

So no problem with engine internals, those seems at first to be at lower side but i have 9.2 pistons and long duration high lift cams with vanos inlet timed at some close to 126-128 values at idle so there can't be much more static compression

Next place to search is propably dme but first i plug inpa to the car and so some securing during voltage feed etc

 

[Bnks334]

Search continue, misfire issue is not triggered by injection window and single phase injection does not work as expected.
I did to be sure measurement of cylinder pressures with digital pressure meter and

Cyl 1 9.05
Cyl 2 9.15
Cyl 3 9.45
Cyl 4 9.25
Cyl 5 9.20
Cyl 6 9.40

So no problem with engine internals, those seems at first to be at lower side but i have 9.2 pistons and long duration high lift cams with vanos inlet timed at some close to 126-128 values at idle so there can't be much more static compression

Next place to search is propably dme but first i plug inpa to the car and so some securing during voltage feed etc

I only see the one log posted.... and in that log I see around 5,000rpm you have a throttle closure? I imagine at these power levels and modifications a throttle closure mid pull will change the airflow in the manifold quite a bit. Any chance you considered that at all?

 

[135boost]

Thank you to react and throw notifications to this issue irritating every one in power levels high enough
i will post more logs regarding this issue.

about throttle closures, we fixed that with P33P33, some small adjustmests to throttle closure aggression tables and fine tune
few other tables, it did not solve that misfire so search continue.

i will next test with heatsinks to DME mosfets and DME cpu`s to reduce intenal temp of those if that solve something.
there can be some temperature related issues with high rpm high load to injector driver or ignition mosfets and those
are quite difficult to log or measure.

 

[135boost]

okay, one day again with misfires.
to dig out real root cause of this annoying issue, like i started this thread, this is still just fuel,air,squeeze,ign,push,exhaust without any wichcraft.

one hour mission to dig me in to continental FR and pages 910-960 and there is very ... interesting things about this ignition system functions.
if i got it right, it`s not sipmle dwell adjusting, but scaled much to next level complicity monitoring and adjusting of spark.

It start with monitoring coil charge time and voltage rising, that is to be compared to pre programmed table in a limit window.
dme safety circuit calculate amd monitor speed and energy flow to coil, then it decide if coil is charged enough, if that treshold is reached, it reduce or cut the charging process and fire. now if that is compared to stock engine and stock coil values, it for sure cut dwell table values.
then after firing spark, it monitor time and quality of that spark to fit some pre programmed window and it so adjusting to next spark based on those values. for sure there is adaptations to every aspect and like we have on tunerpro xdf file min and max adaptation, there is bunch of other tables too what influence spark duration adn coil dwell / saturation.

there is few more steps to tune dwell time and spark but just to open eyes.

based on that, without any explanations how that all work together and with missing tables, it can be that real coil output in real live is much less than we think because of those background adjustments and for sure that will cause misfires.
possibility is that we buy better coils without any advantage of those if we se coil tests only on testbench what does not take in considering of these background processes.

then monitoring has it`s own specialities, there must be 2 circuits cause monitoring circuit is for only 4 cylinders and we need 2 of those to monitor 6, most likely 3 cyl/ monitoring circuit.

that monitoring work well until it reach level where 3 cyl dwell overrun time of 1 rotation of engine, then it start to throw flag of first noticed
misfire or issue caused of overlapping time.

story is very long but just to throw new perspectives and possible causes of misfires little out of box.

My opinion is that on mhd there should be to monitor dwell and adaptations to it