N54 335 bad idle and dies off

Nas335

New Member
Jan 7, 2018
4
1
0
Ride
'08 e92 335i
Hi guys

I'm trying to diagnose if my lpfp or hpfp is dieng.. one morning car starts and very bad idle and it eventually dies off. It's not like a bad coil or bad plug it's much worse idle that the car dies off.

Now it starts normal and drives normal also so I have no idea what the issue could be. Any insight or help will be highly appreciated.

I managed to get some logs and I am not sure what to look for in these logs.

Mods:
Catless downpipes
Bms dci
Charge pipe and bov
Mhd stage1+
 

Attachments

  • 2018-09-01 19_21_09 I8A0S v7.1 Stage 1 FMIC 91oct_95ronAT_noALP.csv
    13.9 KB · Views: 169

R.G.

Lieutenant
Nov 17, 2016
669
325
0
Henderson, NV
Ride
E92 335, F10 M5
Looks like you are running ethanol and you shouldn't be with that map. LPFP shouldn't be struggling like that on 91 map. Likely cause of rough starts as well.

Log a cold start and post it
 

Nas335

New Member
Jan 7, 2018
4
1
0
Ride
'08 e92 335i
Hi @R.G. thanks for your response

I doubt there's any ethanol in the tank last time i ran eth was 25% and flashed the e25 mhd map and that was in July.. I will log a cold start and post it up

thanks
 

R.G.

Lieutenant
Nov 17, 2016
669
325
0
Henderson, NV
Ride
E92 335, F10 M5
When you unlock the car with the key fob before doing the cold start log, listen if you can hear the faint buzz of the pump priming for a few seconds. There was an update for the dme that programmed the priming.

It's always a good habit to turn on ignition / turn off AC compressor and wait 5 seconds before turning engine on a cold start.

If still happens after those precautions, then you can assume from log posted that lpfp would be a good place to start. Lpfp @ 45 psi on a stage 1 map at that boost level is too low. Let's see what a cold log looks like before throwing cash at issue tho
 

Nas335

New Member
Jan 7, 2018
4
1
0
Ride
'08 e92 335i
Attached is cold start log..

Car had a slight miss fire read codes..

The lpfp does still prime I hear it when I unlock the car
 

Attachments

  • 2018-09-04 08_25_22 I8A0S v7.1 Stage 1 FMIC 91oct_95ronAT_noALP.csv
    296.3 KB · Views: 167
  • Screenshot_20180904-083107.jpg
    Screenshot_20180904-083107.jpg
    136 KB · Views: 178

matreyia

Major
Apr 19, 2017
1,750
686
0
Ride
335i e93
Hi guys

I'm trying to diagnose if my lpfp or hpfp is dieng.. one morning car starts and very bad idle and it eventually dies off. It's not like a bad coil or bad plug it's much worse idle that the car dies off.

Now it starts normal and drives normal also so I have no idea what the issue could be. Any insight or help will be highly appreciated.

I managed to get some logs and I am not sure what to look for in these logs.

Mods:
Catless downpipes
Bms dci
Charge pipe and bov
Mhd stage1+


Run error/fault check to see codes. Otherwise there is no way to know for certain. I use schwaben tool or carly bmw.