Sputtering/misfire cyl.1 couldn’t be fuel pump?

Tonynotoes

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Jun 12, 2024
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I noticed my car was sounding different when I accelerated hard and felt a loss of power from 4-5k rpm for a few weeks, maybe even a month. plugged in a few days ago and it was saying cylinder 1 misfire, with no other info. a couple days later I topped up the coolant a small amount and everything went back to normal, I really think that is a Coincidence but my car was pulling like a train again. I’m stuck, I’ve ordered an MHD scanner, here’s the LPFP log. Please if anyone could help

If anyone has any sort of ideas or has the same problem let me know. Me and my mechanic are struggling because the codes are useless and I don’t want to throw £££ at it if I don’t know what the issue is.

Some info on the car itself

2006 e92 bmw 335i 135k miles

MHD stage 2

Turbos replaced with oem bmw 130k
 

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I wouldn't say that the O2-sensors are okay. Like I said, those kind of lean conditions would grenade the engine instantly, if the car even ran that lean. That lean would be way too little fuel to even drive the car.

The LPFP seems to be fine. On the first log it got little low, but nothing alarming.

And it is understandable that you don't want to drive the car to not break anything. So no worries there. If the O2-sensors are malfunctioning and are the cause of the issue, the car should run way smoother (not perfect obviously) on the open loop mode when they are unplugged.
So the issue is fuel related from the logs. Okay that’s a good step in the right direction. That’s good to know.

Yeah I don’t know why that was. From the...

Tonynotoes

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Jun 12, 2024
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Hi,

Did you figure out the problem? I haven't been active since I was on work trip over seas. Sorry for that.
Hey bro, disconnected the sensors. Still gettin the issue. But I’ve noticed on the logs the fuel pump dropping to 40-50psi which I don’t think is good at all. Will send the logs on here. Lmk if u have any ideas or see anything that doesn’t make sense on the logs bro, hope you’re well. Thanks for replying haha



 

odesh

Specialist
Mar 6, 2023
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Hey bro, disconnected the sensors. Still gettin the issue. But I’ve noticed on the logs the fuel pump dropping to 40-50psi which I don’t think is good at all. Will send the logs on here. Lmk if u have any ideas or see anything that doesn’t make sense on the logs bro, hope you’re well. Thanks for replying haha



Yeah, you are right. The low pressure pump seems to be going down and bringing the rail pressure dangerously low as well.

Are you still running the original fuel pump?
 

Tonynotoes

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Jun 12, 2024
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Yeah, you are right. The low pressure pump seems to be going down and bringing the rail pressure dangerously low as well.

Are you still running the original fuel pump?
Yes bro never been changed I don’t think. I deffo haven’t done it. All my mates been telling me it the fuel pump the whole time haha. But I think because I reset all adaptations it started working again for a few weeks. What do u think I should do? Replace? Walbro 450? Hopefully this means I don’t need to upgrade the hpfp as well😫 anything else catching your eye? Gotta put her in the garage soon for steering rack and oil leak so just gonna buy the fuel pump and do it all at the same time..
 

odesh

Specialist
Mar 6, 2023
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Yes bro never been changed I don’t think. I deffo haven’t done it. All my mates been telling me it the fuel pump the whole time haha. But I think because I reset all adaptations it started working again for a few weeks. What do u think I should do? Replace? Walbro 450? Hopefully this means I don’t need to upgrade the hpfp as well😫 anything else catching your eye? Gotta put her in the garage soon for steering rack and oil leak so just gonna buy the fuel pump and do it all at the same time..
Your HPFP should be fine. Could you get an used fuel pump from somewhere? Would be a shame to buy 450 just to find out that it's not the problem :/
 

Tonynotoes

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Jun 12, 2024
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Your HPFP should be fine. Could you get a used fuel pump from somewhere? Would be a shame to buy 450 just to find out that it's not the problem :/
Even if it’s not the pump it will still need it it eventually. Worst case could be the injectors? I’m gonna order the walbro/sparks and coils first, see if that sorts the problem . Hopefully should get that done over the next few days.
 

Tonynotoes

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Jun 12, 2024
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Even if it’s not the pump it will still need it it eventually. Worst case could be the injectors? I’m gonna order the walbro/sparks and coils first, see if that sorts the problem . Hopefully should get that done over the next few days.
Also here’s another log from today, lpfp is going from 72psi when normal driving and 45psi when high rpm then to 80+psi after the pull. Strange. Lmk if u see anything different

 

AzNdevil

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Staff member
Nov 4, 2016
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Hong Kong
Also here’s another log from today, lpfp is going from 72psi when normal driving and 45psi when high rpm then to 80+psi after the pull. Strange. Lmk if u see anything different


car is in open loop, o2 sensor readings are stuck and stft hasnt completed learning cycle stuck at 0. drive more and take a log

1722450003218.png
 

wheela

Captain
Jun 4, 2021
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Twin Cities, MN
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2015 e84 X1 35i Msport
Hey bro, disconnected the sensors. Still gettin the issue. But I’ve noticed on the logs the fuel pump dropping to 40-50psi which I don’t think is good at all. Will send the logs on here. Lmk if u have any ideas or see anything that doesn’t make sense on the logs bro, hope you’re well. Thanks for replying haha



What sensors did you unplug?