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JapSpec JapSpec is offline
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Default n54 Single turbo Misfire at high RPM - 09-13-2019, 05:31 AM

i've been having a misfire issue when i pass 6700 rpm. on Map 5
the setup is a 07 335i automamatic
JB4/MHD
JP workz 6266 turbo
BMP port injection with JB4 PI controller
BMP stage 3 LPFP
VRSF Race Intercooler
VRSF Chargepipe
3.5 Tmap BMS harness
BL coil / NGK 2 step colder plug gap to 0.20
Fuel E85

i can see that my LPFP is not that healty i have a new walbro 450 pump coming so ill replace that.
but maybe you guys can see something else what could it be
Attached Files
File Type: csv 2019-09-12 22_48_06_Map-5.csv (9.7 KB, 20 views)
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Default 09-15-2019, 09:55 PM

Does the miss happen on lower boost maps?



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e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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Default 09-16-2019, 04:49 AM

Quote:
Originally Posted by Dave @ BMS/Fuel-It!
Does the miss happen on lower boost maps?
no not really on map 2 map 3 is good. map 4 sometimes it does misfire.
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Default 09-16-2019, 12:42 PM

Have you tried closing your plug gap a bit? .018



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e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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JapSpec JapSpec is offline
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Default 09-16-2019, 07:08 PM

Quote:
Originally Posted by Dave @ BMS/Fuel-It!
Have you tried closing your plug gap a bit? .018
Yes I have now on .018 still same
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Default 09-16-2019, 10:10 PM

Misfire might be fuel related, although your HPFP looks really solid up top.

How longs it been doing it?

Could be false Knock too, especially at your boost levels...knock sensors still on?



http://www.fuel-it.biz/

e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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Default 09-17-2019, 01:23 AM

Quote:
Originally Posted by Dave @ BMS/Fuel-It!
Misfire might be fuel related, although your HPFP looks really solid up top.

How longs it been doing it?

Could be false Knock too, especially at your boost levels...knock sensors still on?

when you said fuel related. what you mean by that? and is there adjustment I should I change on fuel bias?
itís been misfire since I been running higher boost than 20psi
but if shift it 6500 rpm no misfire anything higher it will.

and yes knock sensor still on.
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Default 09-20-2019, 07:25 AM

Fuel related meaning it could be, never rule it out- but as stated your HPFP values look solid & it looks like you’ll be replacing your walbro.

To me it almost seems like it could be false knock causing the misfire



http://www.fuel-it.biz/

e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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Default 09-20-2019, 07:37 AM

Quote:
Originally Posted by Dave @ BMS/Fuel-It!
Fuel related meaning it could be, never rule it out- but as stated your HPFP values look solid & it looks like youíll be replacing your walbro.

To me it almost seems like it could be false knock causing the misfire
thanks Dave, i just replace my LPFP it seem to be good now. but Misfire still happen.
is there a way to diagnose the false knock? and what could it be the causing of the false Knock?
Attached Files
File Type: csv 2019-09-18 22_36_45_Map-4.csv (7.8 KB, 10 views)

Last edited by JapSpec; 09-20-2019 at 08:01 AM..
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Default 09-20-2019, 09:41 AM

Quote:
Originally Posted by JapSpec
thanks Dave, i just replace my LPFP it seem to be good now. but Misfire still happen.
is there a way to diagnose the false knock? and what could it be the causing of the false Knock?
What clutch are you using- is it a DMFW?

index injectors?



http://www.fuel-it.biz/

e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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Default 09-21-2019, 04:51 AM

Quote:
Originally Posted by Dave @ BMS/Fuel-It!
What clutch are you using- is it a DMFW?

index injectors?

It's a automatic with xhp stage 3 flash.
Index 12 injectors
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Default 09-23-2019, 07:24 AM

We may want to try pulling your cyl 6 injector & swapping it to say 5.

I wonder if your cyl 6 injector flow is off



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Doc Race Kit 6062
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