[2GDSM1997]

Just recently purchased a 2011 335i (n55), currently going through and fixing the previous owners mistakes. Cars throwing these codes and I’m trying to diagnose it. On cold startups car almost dies after starting. It revs up to 1000-1100 on startup then drops to about 400-300 rpm. While driving when putting the car into neutral (6MT) car will drop all the way down to 400-300 rpm, jump back up to 1000, drop again, then raise back to a normal idle. (Logs of coming to a stop in neutral show a drop in mean rail pressure). I also have some CRAZY timing corrections (see screenshots of log). I have replaced the rail pressure sensor. Any clue what could be happening? I don’t want to just throw a hpfp at it without making sure that’s the issue. I also found these wires spliced and taped up in the fuse box under the hood. I believe it’s for jb4. Could that be causing an issue and if so what do I do with the wires ? Any help/diagnostic advice/input, anything would be helpful !

[konstat]

Originally Posted by 2GDSM1997

Just recently purchased a 2011 335i (n55), currently going through and fixing the previous owners mistakes. Cars throwing these codes and I’m trying to diagnose it. On cold startups car almost dies after starting. It revs up to 1000-1100 on startup then drops to about 400-300 rpm. While driving when putting the car into neutral (6MT) car will drop all the way down to 400-300 rpm, jump back up to 1000, drop again, then raise back to a normal idle. (Logs of coming to a stop in neutral show a drop in mean rail pressure). I also have some CRAZY timing corrections (see screenshots of log). I have replaced the rail pressure sensor. Any clue what could be happening? I don’t want to just throw a hpfp at it without making sure that’s the issue. I also found these wires spliced and taped up in the fuse box under the hood. I believe it’s for jb4. Could that be causing an issue and if so what do I do with the wires ? Any help/diagnostic advice/input, anything would be helpful !

What does your low fuel pressure look like at idle? A high pressure of 650psi at idle is normal (in my N54 at least).

Your AFR is definitely lean like that code is suggesting. Are your O2 sensors maybe junk? However, that wiring job in the ECU also looks sketchy, that could be the cause of your issues. Your 3847 code mean bus error, i.e., CANBus which is what automotive electrical architecture is based on and I bet is because of that junk wiring/splice job. Are confident doing a proper splice? i'd look some procedures up on youtube of a general electrical splice. There are also splice clips available at home depot that you could try to at least see if that's your problem.