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]

don`t worry mr_kraka, i`m humble and just impressed about all of yours skill to dig in to this kind of problems.

my opinion is that this kind of problem solving need different kind of skilled team and approach to solve out them and i think this kind of forums is stupidly good for it.

and yes, multispark is disabled at temp over -48c

these kind of question is quite ofen those eyeopeners because in troubleshoot world people has tend to search faults
deep in to something and obvious solution sitting just under their nose,

if this TD_CLC was this root issue to this, there for sure is some better table to tune than this ect factor for dwell time
but seems odd that there is not so ever discussion of that whole TD_CLC issue on any discussion forum and before carabuser dig out monitoring for it, no one has even been interested on dwell real value, just put dwell to table and lean that it`s done with it and at the end we just buy coil after coil and injector after injector and caused on their small variances some hide issue and some not.

when i found that picture from FR page 934, it just stunned me that this piece is alter coil charge phase with compare it to something and then i had long discussion with P33P33 about that there is possibility that in real world we don`t have a clue about real dwell time and that is not monitored by INPA or MHD.

like i told some numerous posts ago, i think root cause for misfires was not found, and we just struggle to mask real issue best way we can and maybe this is the root cause and if so, thanks goes to carabuser for that MHD logging possibility.

if this is a issue on N54, you can count on it that same kind of logic lies behind every DME, and cal be in use at least in these DI turboengines like N55, S55, B58, S58 and so on with compairing values from their orginal coil dwell and saturation profiles

on xdf there has been whole time visible at least that ect factor.


before i got a chance to test this (raining here so small traction issues with 3-4 gear wot at 6000 plus rpm)
i think we all hope this put our misery of odd misfires to end.

i will log cruise at different speed this morning m yesterday dw was at start 2.80ms and some 30sec and it fell to 2.15-2.24 levels

to those mhd logging possibilities, i try to find time to follow logic path if i find more of intersting logging values

××××××××××

datazap.me | Maantec | Log 1634271775

datazap.me

Log from this morning, 3.00to 3.40ms dwell, i has to do some adjustments to rpm dwell scale.

That 3.40 is because i had it on my dwell table.

I edit one earlier post regarding temp factor toobased on this morning tests, seems to be at least on my dwell table ect factor combo that all over 1.600 throw there over 6ms dwell so there is some limit and after that it take some constant value, i think the calculation is dwell table x 1.6 ect factor mean close to real value and those 1.0 is dwell table divided by 1.6. For sure there is some calculation logic behind this and this is maybe my values that throw these numbers but again, foe gods sake, DO NOT ALTER ECT FACTOR WITHOUT MONITORING THAT TD_CLC

 

[135boost]

Carabuser, one stupid question, there is torque act value in mhd to be logged, is it possible to do a separate hp value too like that torque x rpm / 7140 to be logged

 

[carabuser]

I don't think you can do calculations in the MHD logging. There's potential to do that calc in the ECU but I don't think it has any value as modelled torque will be inaccurate in most tunes as they either alter the efficiency calcs or mess with reported load.

 

[135boost]

Okay, it was just taught that if not touch load to torque tables there could has been compairing log to log, and maybe syncronise
it to local low reading dyno values and then compare if something in parameters (not load to torque) is altered, how that react.


about real logging
PRM_TI cylinder individual injection time, this should be total injection window
LV_INH_INJ [NC_CYL_NR] Flag that indicates if cylinder shut off is active or not, maybe useless too
NC_INJ_MOD_HOM Constant defined to indicate homogeneous mode, i think these all run just that homogenous mode so this can be useless too


XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
tables for random misfire sequence, what the fack...
not to be logged

ID_RND_PAT_MIS_GEN V 0... 1H 0 ...1 1 -
LDP_X_ID_RND_PAT_MIS_GEN 16 0... FFH 0... 255 1 -
LDP_Y_ID_RND_PAT_MIS_GEN 16 0... FH 0... 15 1 -
Table of Boolean to define the pseudo random misfire sequence

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

 

[carabuser]

Car is always in homogenous mode. You can verify that by looking at the "Fuel Mode" param in MHD logging, 2 means homogenous mode.

LV_INH_INJ [NC_CYL_NR] is just a reference to bits of inh_inj.
If bit 0 of inh_inj is on then that means injection is inhibited in cylinder 1. I've added this to the custom logging file so you can monitor that.

PRM_TI wouldn't be any use to you. It's a just a parameter in a subroutine that's called per injector so the value is constantly getting overwritten when the routine is called for the next injector.

There is 3 injection pulses so you might want the values for each pulse and for each injector.

TI_1_STND_HOM [NC_CYL_NR]
TI_2_STND_HOM [NC_CYL_NR]
TI_3_STND_HOM [NC_CYL_NR]

I think these are the final values but the Continental documentation is a pain to read compared to the BMW one. Take a read and see if those are suitable and I'll get those addresses.

 

[135boost]

I looked at that continental FR and noticed that there was 3 pulses and taught PRM_TI was those combined but there was more than just 3 pulses, this can do low needle lift and high needle lift pulse and maybe mix those high and lows and what i understand, soi of every pulses can vary so it's not so easy task to get monitored total pulse widht what i was after there.

At the end, about missfire, this need those few elements to burn, air, fuel, squeez, ignition and squees is there for sure, same with air and now thanks to you carabuser i can monitor ignition path all to dme output..


****************************************************
okay, testing continue...
first, those ect values and their effect on dwell times, logic seems to go dwell table-->compare it to td charge map-- > ect factor -- >compare to min and max td adaptations --> dwell value.

at first i did alter that ect_factor and yes, it affect dwell value like i described some posts ago, then P33P33 suggested to alter that adaptation value and put those both to 0 cut away that ect factor influence, maybe something else too but real dwell values and
ect factor straight 1.000 in every cell and min /max adaptation to zero give output as to that orginal dwell table.

****************************************************
test 2

carabuser, you added that INH_INJ log to my MHD, that value stays at zero untill deceleration is done with fuel cut off where value jumps to 63 so i don`t think there is much value on that except that it`s indicate injector shutoff in case of deseleration.
i think that is more like a value to shut off all injectors but if issue is a injector, issue then is injector by injector output more than all 6 of them cause it does missfire one there and one here, not all of them at the same time.

i will still test that value and what it throw if i has that misfire still there.

it can be that there is no way to do total injection time calculations at whole rpm load range and at least what i figure outbut from FR i taught that PRM_TI would be closest to it but obvious i was wrong.
then i assume this dme jumps to 1 phase injection time like diesels cdi engines in some stage of load/rpm levels with very complex routines and my best guess is that it`s first of those 3 injection phases what it use and injection mode is high needle lift so maybe it`s TI_1_STND_HOM [NC_CYL_NR] what should be monitored.
I`m not sure about logic but at least diesels has 3-4 phases , like ignition phase, power srtoke phase, 3 end phase and then separate DPF burn phase and when rpm rises, it moves proportionally to 1 phase injection and i think this behave same way without that DPF stage.

to monitor what really is missing on those air fuel squeez ignition, my opinion is to separate DME from engine hardware in search of real root cause and therefore we should at least know ignition dwell and timing is commanded from DME and injector phase pulse widht or total injection time to know that DME has intend to trig ignition with energy enough and injector pulse to spray fuel enough to keep AFR in target.

if we know last stage of DME signal it to happend, then it`s more likely to dig in to engine, thankful to carabuser we got monitoring possibility to dwell so that is not a issue, then we need to know that DME command injection pulse to stay steady in those misfire situations, if so, then again dig in to engine hardware.

what is not been monitored pulse by pulse is crankshaft position sensor but i assume that`s more like oscilloscope thing because it`s known to escallate issues on manual with flywheel vibrations. it can be root cause too to quite many stupid and very difficult to find issues.

for damn, this root cause finding can`t be so difficult


throwing more thinkable things to this discussion, page 4776 in continental FR, coil diagnosing, C_ABC_MAX_TD_IGC
and C_ESB_IGN_CUT_DIAG
those can too be reason for some misfire cuts,

in these situations, C_IGA_OFF_CYCNR_HLD is a value of duration to regeneration and therefore if misfire detection is off, it will restart
coil again.

like i told, with misfire detection off, it recover cylinders after misfire in same pull, i have that issue now at prox 6130rpm and at some 7000rpm it recover.

there is C_SUM_IGC_SCP this 8 bit value what act as counter, maybe start to switch it to 255 to increase time to trig misfire coil switch off,
or redyce duration C_IGA_OFF_CYCNR_HLD to short it out if that has some effect to this issue and last if nothing else affect, C_ESB_IGN_CUT_DIAG as test purpose to be sure misfire is not about those values used in normal bin file.


on page 6209 we have crankshaft oscillation diagnose too

C_N_MAX_CRK_OSC there is max rpm to diagnose crankshaft oscillation, i think it`s now at max 8160 but if that is reduced to 5000? what will happend, does it reduce manual trans flywheel issues, does it affect this other mystery misfires ??

then i think LV_STATE_RR = 1 (rough road detection should be active all time to prevent car vibration effect to these misfires.
that can cause issues on harder suspension springs, violent accelerations etc situations and on level of 700+hp it maybe trig that so 1 is on my opinion right value)

i`m not sure if lc_mis_inh will deact rough road detection or not and how it affect those other values like oscillating issue?

maybe combo LC_MIS_INH and LV_STATE_RR could be something to test, i just don`t have skills to add LV_STATE_RR to tunerpro bin
that other is allready there.

 

[carabuser]

I can also find any of those toggles if you and p33p33 are having issues locating them.

 

[135boost]

Here is few to have as diagnosting purpose.
There is in normal mhd logging most of values what is needed for tuning but then when there is
This kind of issue, like you told before, need some custom logging values.

At start, it vas very supricing that dwell was not possible to log, now that other value what to be
Very informative to know is injection time but because of complex injector phase and lift logic mess, that can be difficult.

These toggles and adustings should be accessable

C_N_MAX_CRK_OSC could be one adjustable thing to reduce if that value is in level of max rpm
That can even be in same rpm that these misfires occure.
Then
LV_STATE_RR this as toggle justt to disable
C_ESB_IGN_CUT_DIAG as toggle to disable misfire diagnose if it's not including in LC_MIS_INH

 

[carabuser]

I'm away from my desktop until monday so will get them then.

Anything LV is a status. Most toggles start with C_

 

[135boost]

some more tests done, that dwell is not root issue, seems that even with 3.200ms b58 dwell it misfires at 6130rpm region.

i think next test should be with that harmonic

C_N_MAX_CRK_OSC could be one to test if it`s just harmonic vibrations, put max rpm to 5000 or something
and then disable this C_ESB_IGN_CUT_DIAG, like i told, possibility is that it`s disabled all ready with LC_MIS_INH.

and oh, offcource, one vital monitoring value should be allways dme feed voltage, that feels stupid that it`s not visible anywhere because that could inform if there is weak battery or problems in dme feed and causing odd issues

 

[iminhell1]

and oh, offcource, one vital monitorinv value should be allways dme feed voltage, that feels stupid that it`s not visible anywhere because that could inform if there is weak battery or problems in dme feed and causing odd issues

Being, I believe, The alternator is cut at higher RPM/Load, monitoring the battery is a very good idea. TBH, it's a far more likely suspect than all the other complicated stuff.

 

[135boost]

That alternator cut didn't even came in my mind, it for sure can escalate issues too, that's why there should be that voltage monitoring

I will today change front drive shafts, support bearing and front wheel bearings ( have those stock) to eliminate harmonic vibrations from those.

 

[MR-KRAKA]

That alternator cut didn't even came in my mind, it for sure can escalate issues too, that's why there should be that voltage monitoring

I will today change front drive shafts, support bearing and front wheel bearings ( have those stock) to eliminate harmonic vibrations from those.

FYI

I haven’t tried it but should be an easy way to quickly monitor alt activity. I would think you would have seen the dwell change based on voltage when you were logging unless you flattened the table out. How this is not a standard logging parameter in MHD has bothered me for some time. With all the auxiliary systems we use on these vehicles we are surely adding unexpected load to the charging system at WOT.

 

[135boost]

there for sure is a indicator for voltage but what is in interest is DME input feed voltage versus that very short moment
where misfire occurs and that`s why one logging parameter should be that voltage.
that voltage on dash is difficult to monitor versus rpm without videoing those cause flatout 3-4 gear with 6000-8000rpm make some other things to do than just follow dash.

dwell seems to follow that table and i didn`t flat it so in case of short of voltage juice, you have right, dwell should rise so maybe it`s ok. monitoring make that much easier than guessing.

about misfires, there was in FR mentioned that there is in taught rough road, harmonic vibrations, electric disturbance, switch goes off, radio etc things, so maybe one big disturbance could be alternator shutoff, not only voltage drop but like electric disturbance?

 

[135boost]

this log was from yesterday. sorry about long log but at the end i do one pull what`s i was to show.
I did some stupid tests, ending up with strange boost curve, i think it was my mistake in tune
but to be sure, i will measure and monitor how vacuum is behaving in wg`s to be sure it`s
my mess.

interesting is that on 400 maf / 5700pm there is some mysterious boost pull from 26 to 10psi
and a ditch in boost target, even if boost target is forward again at 27 psi level. that`s propably
my tune mistake but after that i pull to 7400 without any further missfires so misfires on this depend on load and boost

datazap.me | Maantec | Log 1634747526

datazap.me

 

[135boost]

Raining and storming here whole week so no succes to do more pulls, allmost planned to buy own 4wd dyno
to play with because of this issue.

i have done meanwhile tests with finetune and scale fuel scalar, fuel press etc to be precise as possible to follow 0 line in stft but 16x16 map is little coarse for the purpose in low rpm low load.

in my engine there should be max volumetric effiency in range of 4500-5500rpm but what is interesting is that
fuel scalar has it`s struggle in much lower rpm range, 2000-3000 rpm and just after 3000 it is spot on.

I assume 3000 rpm is spot where this move from multi to single injection phase (this is assuming, maybe carabuser has skills to dig a new log parameter to MHD for that ?). there for sure is room for more fuel because injection time window is for sure not maxxed out at those rpm`s.
If that is the case, maybe that single injection mode rpm should be adjustable to meet engine demands, and i been well aware that it will affect scalar tuning too if that rpm is altered.

I dont suffer so much of that issue because huge turbos and not so much load at those rpm, max propably 130 load or so but with smaller turbos and bigger loads, built engines with high lifts and ported heads that can be some issue.

my scalars in 80-120 load and 2000-3000 rpm is close to 2.01 and fuel pressure is way over 3000 psi and stft is still in level of 15 there, and just when 3000 is surpassed, it drop to 0.

I did to this next tune small changes to injection soi values at those 4-5 cells to advance it by 10 degree because i`m not sure about how it affect in possible second and third injection phase and their soi logic, maybe it move whole injection window or maybe if second injection phase is not moved, it will stretch first by that 10 degree.
i think i should try to figure out whole injection phase logic how it move from state to next and for sure there is too ramp times and high/low needle lift involving what affect fuel quantity what is injected

i can live with that 15 stft but like vargas gc twins or so, smaller turbo guys maybe is in trouble with not get enough fuel injected between 1500-3000rpm range.

 

[135boost]

Had little time for researching of odd misfires and dig my selves more to msd80 FR, what a pain..

chapter 7.39 to 7.41
there is shut offs what is processed in some "cylinder shut off" module
there is 2 different cylinder shutoff sequenses in these, static and dynamic.
for sure immobilizer and ign key is on static side and shutoff is on all cylinders.
lv_igk = 0 then all is shut off

then monitoing
lv_off_iv_mon or lv_err_tmp_mu_mc = 1 all is shut off

those was just not so relevant but then there is bunch of other more interesting things
where there is involved misfire detection, cylinder individual sequential fuel cut offs, engine speed limitation (rpm limiter)etc
what is at most in that dynamic part

first fast torque reduction, this is sequential and will pull indivivual cylinders to shut off
and this is done by torque based patter calculation and this is a repeatable sequence what is done like
needed, shut off cyl x and x, then next rev
still needed and no changes in need, continue shut off cyl x and x
still needed and no changes in need , continue shut off cyl x and x
not needed anymode, continue to monitor if it is trigged again start sequence from start
or need more reduction, calculate more cylinders to be involved.



in this module there is calculated value how many shutoffs

what is in my point of view something to think about, is that there is for logical reason MSB and LSB what pinpoint shutted cylinder
and in these there is 2 banks where that is processed and those is divided bankvice, that LSB can easy explain why it`s cylinder 6
at most what is misfiring or shutted down because of repeated monitoring sequence.

what if this situation is trigged on some kind of torque, knock, or what ever reason cylinder shut off demand, because of that Least Significant Bit
cylinder nubering start shutoff sequence from cylinder 6?

disabling shut off should not be done by easy decisions, there is injector error monitoring what can cause hydrolock, then there is that pre ignition shut off what can cause engine damages, cylinder individual shut off for less fuel, customer cylinder individual shut off (not to me ),
workshop tester shut off, powerbank error shutoff.

that complexivity is overwhelming, i just try to figure out what to monitor to pinpoint logical path where these issues start to escalate.

Tettenborn Frank is propably right guy to ask these kind of things because his name is on some 8400 pages of that FR.


i continue to study...

 

[carabuser]

I think Frank was just the unfortunate document controller that had to piece together all the logic descriptions from each module. I don't think 1 single person at Continental or BMW fully understands the entire DME logic, they must have subdivided it up into several teams.

I spent a day last week going through decompiling and notating the readiness logic and even that is a big task.

There's more logic in these engine controllers than an entire power station. Amazing that they packed it all into 2MB.

 

[QuestFor10s]

@135boost I've been following the thread because I am trying to diagnose my post shift timing corrections on my car, and thinking our problems are somehow related. I'm really interested in helping solve your problem as it may help solve my own. It seems as though now that we are well off the deep end - to which there is no end - it would be helpful to regroup and solve the problem top down. As a software engineer (by day) when trying to solve complex issues something that helps me is to follow a structured approach to problem solving such as divide and conquer. Equally important is to clearly phrase the problem and state. And finally we must be able to reproduce the problem to test our hypotheses.


In looking at your logs each one shows something different, so its not clear what the problem is we're trying to solve. e.g.
log-1634747526: pull to 5700 rpm gets a -2* correction at 5079 rpm.
log-1632370857: pull to 6200 rpm, no timing corrections, overall timing drops 5* at 5762 and another 3* at 6255
log-1632682926: You upped your boost target to 28 psi now, overshoot to 29psi and get 10* of timing pulled at 5686
log-1633894108: boost target 28psi, undershooting to 26.8psi, pull to 6336, timing starting to be pulled at 5747 through 6139, and hit fuel mode 15 (open loop).



State the problem:
--------------------
If you are getting misfires* at the end of each of these pulls and that is why you are letting off then lets state that as the problem. If you are only getting timing corrections, like I do, then lets state that. *And lets define a misfire as being over 11* of timing pull and then the DME shuts down that cylinder. The state of the car must be precisely defined as well, because everyone's car is different. For example: I'm DCT, FBO, 17T, PI, E85, B58 coils, Wedge tune and 135boost is a low compression built engine, G25-660, double barrel, E85, self tuned (quite different!)



Make sure the problem is reproducible:
-------------------------------------------
Can your car reproduce the behavior every time? Are multiple cars affected? This would be even more helpful because it will help us in the next step.



Divide and conquer:
----------------------
Construct tests which factor out systems or isolate the problem to specific systems. The first test I would do is to see if the knock is real. We know the DME uses knock to control timing among other things. So there are only 3 possibilities.

A) There *is* knock present and the DME is correctly reducing timing to save the engine.
B) The noise the knock sensor senses thinks there is knock, but in actuality its just noise. (False knock) and the DME is reducing timing (erroneously).
C) With no knock present and the knock sensors desensitized the DME is still pulling timing due to other reasons.


My hypothesis is that the knock isn't actually real, rather its drivetrain noise and the knock detection algorithm/data in the DME could need to be properly respecified. But we cannot guess or assume, we need real data to guide our decisions. So what I would do is to put another knock sensor on the block and get an objective reading. Either some "det-cans" or a plex system.

 

[135boost]

state of the engine
-fully built 9,2 compression bottom with h profile conn rods and supported
upper end of cylinder bore so there is for sure more noise than ordinary stock bottom end.
-ported head with 230cfm big ferrea valve and schrick high lifts with heavy springs,
-one noise adder is then front diff cause it`s bolted to oil pan.
-one noise adder is second hfpf
-custom made exhaust manifolds to get free flow to those g25-660`s
-1 pc prox 1200cc injector in chargepipe to add some amount of fuel at max rpm max pressure
-berk exhaust, no cats

compression of cylinders is measured, variable was quite minor, some 0.25 bar so no issue on
pistons.

on those logs, what make differences is tune, on same tunes misfires is repeatable and hit every time in same rpm, tested it some 10 times and variables was in some +-50rpm what is fitted in sample rate.

about open loop, it jump to open loop when i get misfires.

what i have tested up to date
-misfire detection off, still issue
-knock detection off, still issue
-different load to torque tables, still issue
-stock, pr and b58 coil, still issue
-different afr targets, still issue
-different plugs and tem ratings, still issue
-swapped 3 different injector sets, still issue

i`m quite sure issue is somehow DME related and it`s some hidden safety "feature".

what i don'´t get is that what all things is trig that ignition pulls, for sure knock sensors and then
transmission limits and it´s logic input to DME
then for sure traction control is messing up that too.

knock is out, same with traction control related modules
-disable torque safety path
-disable torque safety path soft and hard
-disable asr intervention
-disable msr intervention

what i know, transmission software torque limit in tune is raised to 1000nm and max line pressure is reached
at some 600nm and it get that torgue reading from DME load to torque value so it`s more to keep
torque reading well below 1000 but well over 700 to keep transmission from slip causeb by low line pressure

because these issues like misfire, ignition lull etc is repeatable and depending on tune they hit in very narrow load and rpm window, my opinion is that it`s a software logic issue.

i just con`t have skills to pinpointed pull safety module after safety module away from tune to test which is causing ignition pulls and wich misfire.

about MSD81 FR (feel sorry for Frank ) there is logic path after logic path and what is interesting is to find
things like that dwell issue and solve it with capability to monitor it too. like Jyamona in N5x spreadsheet told, log is our best friend and it has a demand to be able to log things.



P33P33 and car abuser did it possible to me to log that value but to find these kind of issues, there is for sure much more values to be monitored too, it´s just skills to build those monitoring modules to mhd.

datazap.me | Maantec | Log 1635703674

datazap.me

This was log from today, misfire at 6130 again in both banks but only wit 3rd gear, and again ignition pull even with knock sensing deactivated and then 4th gear with 2psi less boost and particulate less boost target for some reason, iat is very stable so less boost is not to do with it.