Findings and conclutions about misfires and ignition pulls

135boost

Corporal
Oct 28, 2017
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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 😛
 
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Solution
“We choose to tune bmw n54 in this insanity and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one ... so.. is it even technically possible to increase that 1389 value or is only path port injection

135boost

Corporal
Oct 28, 2017
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Economical vice issue was not so big but workload is a different story, twin g25 with custom manifolds, twin hfpf etc does not make work any easier and as crown that xi.

At the same, did mods to trans as well with now 7 friction E pack at the moment (2 more than stock) as i added 1 more frictions to the rest of packs before.

That e drum is little on lack of space and i had to modify a bunch of parts to get everything fit there.

Free end play at E pack is at least 1mm little depending of force used to push it when measures, that was with very gentle force, i can only hope it's enough
 

135boost

Corporal
Oct 28, 2017
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Issue was something like this
 

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135boost

Corporal
Oct 28, 2017
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Finland
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Be aware, this is experimental so if you mod e clutch, it's with a risks.

To fit 7 frictions instead of stock 5 you need space, frictions is prox 1.6mm, and thinner metals is 1,6mm so 6,4mm is needed.

First, i throwed out shim plate what was leaning to pressure piston, prox 1mm, modified a extra 3.2 end plate to lean against piston to avoid flex, then widened drum seeger groove to prox 4mm counting that minimum what end plate lean to drum teeth is acceptable is some 1.3mm.

Then pressure piston, i shortened it from clutch pack side some millimeters, close to so much there is eccess material before hit steel.

Then i did 6 oil path to that surface like orginal.

From inside of piston, i took some millimeter from stopper surface to get more stroke(explain rest later) and then i did minimal deepening to that surface just to keep spring centered. Be aware of piston thickness issue.

About mentioned piston throw, i have some 1.3mm shim under the axlel locking shim to get that steel pressure plate deeper in to piston.
What i understand, my piston stroke is now reduced by some 1.x mm but i'm well aware of that if this trans goes south, issue is not too thin 300 000 drived friction plate what is calculated to orginal quite long piston travel..

At the end, like i told before, added 1 to all packs except first where added quantity is 2 and if torque rating of stock clutch pack is 600nm, that raise other packs by prox 20% and E pack by 40%
 
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135boost

Corporal
Oct 28, 2017
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So, car is running again and cause of trans clutch pack mods i must reset trans adaptations.
Now there is 2 different adaptations, user learn process and wear compensation adaptations.

I have inpa and there e9x, jump to transmission page, choosed automatic gs19, f6 activate and then i run in to trouble.
I find only f1 from that activate page, no f2 or f3 what should be reset clutch adaptations.

So something is missing in my inpa, what is the easiest way to correct that. I tried to dig different files to determine what cause that but didn't figure out what it was (german language inpa so it's a language issue too to me)
 

MR-KRAKA

Specialist
May 23, 2020
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So, car is running again and cause of trans clutch pack mods i must reset trans adaptations.
Now there is 2 different adaptations, user learn process and wear compensation adaptations.

I have inpa and there e9x, jump to transmission page, choosed automatic gs19, f6 activate and then i run in to trouble.
I find only f1 from that activate page, no f2 or f3 what should be reset clutch adaptations.

So something is missing in my inpa, what is the easiest way to correct that. I tried to dig different files to determine what cause that but didn't figure out what it was (german language inpa so it's a language issue too to me)
Did you try tool32? Not as user friendly but should show all available jobs. It’s not too bad once you figure out the navigation. I use the Google translation app camera function to assist if I’m unsure of anything. Be careful you can cause yourself some headaches clicking away with it.

Should go roughly like this…
Open inpa make sure connected,
Open Tool32 -> open .prg file gs19 or whichever is related to your gearbox.
Single click Steuern->argument wizard-> Drop down menu to Adaptionswerte_Loeschen-> run job. I’m sure there’s more you’ll want to do in your situation as well there. Make sure to follow the driving procedure once reset.
 

135boost

Corporal
Oct 28, 2017
243
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Finland
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No panic anymore with this, i got ista p to work and resetted trans adaptations, trans behave very odd now before it adapt new values and that can take it times.
##########################################
No luck with tool32 either, there is something missing in my diagnostic laptop.
I suspect files Gs19.prg, gs19.ipo or something related to those is too old or someway restricted.

First size is 770kb and second is some 68kb., maybe there is some newer or better versions to download
############################################
 
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MR-KRAKA

Specialist
May 23, 2020
85
55
0
Here is what I have for GS19 files the .prg files go in C:\EDIABAS\Ecu folder and the other .ipo etc in C:\EC-APPS\INPA\SGDAT there are several variations so if you only had the one that could be your issue. Best to check to see what you have in those folders first before replacing the files with these. Depending on software versions it may not play nice together.
 

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