[mukoandr]

Hi guys,
to cut things short all coils, plugs & injectors 1.5 month old (oem)
problem i have is cyl1 misfire during acceleration, usually at 3-4k rpm (peak load); car drives normally if you don't push hard and cold start also looks fine
i tried switching coil/plug & injector - same thing

below is 3 logs, any comments what could be wrong?
https://datazap.me/u/mukoandr/log-15...?log=0&data=13

Car: BMW 335is, 25k miles on the clock, 2012
Mods: FMIC, DP, charge pipe, upgraded LPFP, high flow air filter and secondary cats also deleted
Fuel: RON98 (European 98 Octane)


Thanks!

[335e92tx]

what logging tool you got? Not a lot of common default variables there. Where did the map come from?

[Wolf 335]

Injectors are latest revision-12?

[mukoandr]

injectors yes, latest version (12); i doubt it could be injectors as they are 1.5 month old, but i will try to swap cyl1 with cyl3 today

logging tool cobb v3 and map stg 2 sport

[HawkeyeGeoff]

Have you checked your plug gap and checked to make sure the crush washer on the sparkie actually crushed and isn't finger tight?

I had a moment when I thought I torqued the sparkies down correctly and in fact they were not; I switched from using the torque wrench to the ol' hand wrench guesstimate method that i've been using for 10 years. No problem since.

[mukoandr]

i used torque wrench and torqued 18nm. i tried swap plugs/coils and nothing really changed
If you look at datazap you will see that my hpfp pressure drops materially vs requested, biggest question is what is causing it, ie bad hpfp itself or something else...

[HawkeyeGeoff]

quote from here: http://www.n54tech.com/forums/showthread.php?t=21269

FP H: Fuel pressure, high system. Otherwise known as the high pressure pump. Note all N54 include this and other platforms can only log this if also equipped with the flex fuel connector. This value represents the voltage of the high pressure 0-5V sensor, where a value of 20 is 5v. Each unit of measure is roughly equal to 150psi. Typical values at full throttle are 10-14, or 1500 to 2100psi. Values of less than 900psi as full throttle indicate a fuel delivery problem and the JB4 will failsafe at 700psi at full throttle. Note when not at full throttle a typical value is 5 or 750psi.

Maybe on the low end for it....

[mukoandr]

you could be right #7, during misfire and full-load my LPFP is holding up at ~450-500 kpa (~70psi) which is totally fine i guess, BUT HPFP dropping to 10000-12000 kpa (1450-1750 psi) versus requested 17000 kpa or 2450 psi, so an error of 35% which is a bit too high i guess..

problem is i am not very experienced in reading logs, would appreciate comments from the ones who is a bit better at this

Thanks!

[RSL]

It's a little low, but doubt it's the source of misfires. What plugs did you put in, stock heat range or colder? If colder, 1 step or more? It also occurs where actual load exceed request, though that might be a long shot. Try another map, like Stage 1, 1+ or 2 and see if it continues.

[mukoandr]

plugs stock ones; i already tried map 0 v stg 2 - same thing
contacted Cobb, unfortunately not much help from them
will try to swap injector and see how it goes (maybe miracles happening and injector failed after 1.5 month...)
will let you guys know how it goes

[mukoandr]

update
swapped cyl1 injector with cyl6 injector and no misfires anymore
hpfp pressure not perfect, but much better
i still can't explain why cyl6 not misfiring, cobb saying i should check plug as that may have just been loose or could have some wiring that is less than perfect

not yet sure how to check wiring, but i guess need to keep looking at the issue

[335e92tx]

Originally Posted by mukoandr

update
swapped cyl1 injector with cyl6 injector and no misfires anymore
hpfp pressure not perfect, but much better
i still can't explain why cyl6 not misfiring, cobb saying i should check plug as that may have just been loose or could have some wiring that is less than perfect

not yet sure how to check wiring, but i guess need to keep looking at the issue

Wire to coil?

glad its better.. these things are finicky.

[mukoandr]

yes wire to coil, will try electrical wire cleaner or something like that; don't believe its the issue but who knows..
anyways will keep looking and report if find I find anything; car now feels a bit low on power so need to get back my hp

[HawkeyeGeoff]

Wouldn't be the worst idea in the world to check compression if you take the sparkies out again either.