Fuel Pump or Injector?

Injector, Fuel-Pump (HPFP), or Both?

  • Injector

    Votes: 3 75.0%
  • Fuel-Pump (HPFP)

    Votes: 1 25.0%
  • Both

    Votes: 0 0.0%

  • Total voters
    4

Fluxil

New Member
Jan 20, 2019
8
1
0
Ride
BMW 335i (E92)
So, the other day I was leaving and my N54 335i cranked as usual. Then it started having a rough idle, bouncing between 800-400rpms, then eventually it stalled out and died. A few days later I went out to start it again and it did the same thing. Except for this time I gave it gas to keep it running. I through a 29cd code, misfirings on cylinder 1. This time I kept clearing the codes and giving the car gas to get it to stabilize. After about 1-2 minutes of doing this, it finally stopped throwing the codes and stabilized. After that happened I began to log to search for anything. Throughout the log, I would blip the throttle to about 3k and let it resume idle. Mostly to see if it would misfire under low stress. It is important to note that it has been below freezing and rain has frozen on the car, and snowed the days this happened.

During the warmer days, it never did this. Actually, this is the first time it has misfired since I first go it. Aside from an overboosting code it threw when it was still warming up and I was doing highway speeds. My first thought was it could be a leaking injector, and many seem to agree with this. I also uploaded the log here to see if someone a little more proficient could look over them and tell me what they think. I noticed that my LPFP (fp-l) seems to be in the normal pressure range. However, my HPFP (fp-h) looked alright at first glance. But noticed it dropped below 5 (4) after sometime idling. I did not think this could cause a misfire, just trying to cover my bases.

Car has JB4, DCI, Chargepipe w/HKS Bov, new spark plugs, new coil packs, new battery. I know some of this is completely irrelevant to the misfire, just covering my bases in case I missed something here.

Any insight would be greatly appreciated. Again it has been below freezing and will be going out sometime in the next day or so to start it up to warm it. This time I will be logging the crank to see if the issue repeats.
 

Attachments

  • 2019-01-16 17_20_59 Map-5.csv
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matreyia

Major
Apr 19, 2017
1,747
685
0
Ride
335i e93
So, the other day I was leaving and my N54 335i cranked as usual. Then it started having a rough idle, bouncing between 800-400rpms, then eventually it stalled out and died. A few days later I went out to start it again and it did the same thing. Except for this time I gave it gas to keep it running. I through a 29cd code, misfirings on cylinder 1. This time I kept clearing the codes and giving the car gas to get it to stabilize. After about 1-2 minutes of doing this, it finally stopped throwing the codes and stabilized. After that happened I began to log to search for anything. Throughout the log, I would blip the throttle to about 3k and let it resume idle. Mostly to see if it would misfire under low stress. It is important to note that it has been below freezing and rain has frozen on the car, and snowed the days this happened.

During the warmer days, it never did this. Actually, this is the first time it has misfired since I first go it. Aside from an overboosting code it threw when it was still warming up and I was doing highway speeds. My first thought was it could be a leaking injector, and many seem to agree with this. I also uploaded the log here to see if someone a little more proficient could look over them and tell me what they think. I noticed that my LPFP (fp-l) seems to be in the normal pressure range. However, my HPFP (fp-h) looked alright at first glance. But noticed it dropped below 5 (4) after sometime idling. I did not think this could cause a misfire, just trying to cover my bases.

Car has JB4, DCI, Chargepipe w/HKS Bov, new spark plugs, new coil packs, new battery. I know some of this is completely irrelevant to the misfire, just covering my bases in case I missed something here.

Any insight would be greatly appreciated. Again it has been below freezing and will be going out sometime in the next day or so to start it up to warm it. This time I will be logging the crank to see if the issue repeats.

With your current info on he car, it is not possible to give advice. You need fuel type and ratio, coil type, plug type, gap info, old or new sensors for both fuel pumps?, upgraded or stock vacuum hoses, etc.
 
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Reactions: Fluxil

Fluxil

New Member
Jan 20, 2019
8
1
0
Ride
BMW 335i (E92)
With your current info on he car, it is not possible to give advice. You need fuel type and ratio, coil type, plug type, gap info, old or new sensors for both fuel pumps?, upgraded or stock vacuum hoses, etc.

Sorry about that. Currently, I am assuming everything is stock (aside from what I have done). I run 93 octane gas through it. Plugs and coils are both Bosche. From my understanding, the plugs come pre-gapped. I do not know what that come pre-gapped at, but I would assume for a stock motor. Not the recommended 0.22.
 

matreyia

Major
Apr 19, 2017
1,747
685
0
Ride
335i e93
Sorry about that. Currently, I am assuming everything is stock (aside from what I have done). I run 93 octane gas through it. Plugs and coils are both Bosche. From my understanding, the plugs come pre-gapped. I do not know what that come pre-gapped at, but I would assume for a stock motor. Not the recommended 0.22.
Are you using the recommended oil?
 
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Reactions: GreyNBlueE92

GreyNBlueE92

Corporal
Oct 3, 2018
197
50
0
24
OH
Ride
2007 E92 335i
Probably an injector if they have never been replaced and you have coils and plugs already. Personally I'd read the plugs and go from there. Maybe post a pic... Grab the index number off the injectors while you're in there.
 

Fluxil

New Member
Jan 20, 2019
8
1
0
Ride
BMW 335i (E92)
Update:

I went out to start today, misfired on cylinder 1. Same symptom as previous experience. Rather, this time it only acted up after the start. I cleared the code and it smoothed out. Another thing to note is after I cleared the code I kept reading the codes for a couple of minutes after and got misfires on cylinder 1 and 4, then a code for multiple. Cleared those and it did not throw another misfire code. I added a logs link below. I started logging prior to cranking so everyone could see the misfire.

https://datazap.me/u/fluxil/injectors-or-fuel-pump?log=0&data=1-10
 

silverstreak18

Corporal
Jan 3, 2018
126
65
0
Charlotte, NC
Ride
2016 M3
FWIW a HPFP that is going bad will show itself in very cold temps. When you first start the car rail pressure should climb to over 2000 psi for some time, then drop down to around 700-800.