[drivetolive]

Have done an extensive search but am posting before I start throwing money at the car as I cannot find a definitive answer. Car is a bone stock 2011 335 with 160,000km. Spark plugs were replaced as preventative maintenance 5,000km ago.

The car continuously throws a "engine malfunction, reduced power" sign. The car has noticeably less power, but still drives smooth (i.e. no misfires). It does idle a little funny (have to be paying close attention) and developed a long crank last week prior to the CEL.

I have pulled the following codes via a generic OBDII scanner:

P0087: Fuel Rail/System Pressure - Too Low
P10D9: Fuel Rail Pressure Sensor Signal Stuck (Bank 1)
P0300: Random Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0302: Cylinder 2 Misfire Detected
P0304: Cylinder 4 Misfire Detected
P0301: Cylinder 1 Misfire Detected
P15DF: Cold Start Fuel Pressure Too Low (Bank 1)


For what it's worth, when I pulled the plugs, there was no sign of fuel on them.

So what is the most likely answer? Or, what tests can I do to narrow down the possible culprit(s)? Last thing I want to do is starting going down a rabit hole of parts related to HPFP, fuel sensors, coil, injectors, etc .

[TunafishE93]

I would start with the fuel, this can cause the missfires. Its either the high pressure fuel sensor or the high pressure fuel pump.

[gbalthrop]

ANYONE with a 335i/xi got INPA?
Can't INPA, connected to MSD80/81 DME on N54, or the N55 DME MEVD176K/ 1726 read Fuel Rail Pressure Sensor Signal?

The sensor sets TWO different Fuel Rail Pressure Faults: (1) Low Rail Pressure, & (2) Stuck Sensor Signal. ISTA Definitions for those three codes indicates LOW Rail Pressure (1) BEFORE Engine Start, (2) Immediately AFTER Cold Start, and (3) Rail Pressure Sensor Signal PERMANENTLY Stuck, as well as "Implausible" signal. It would seem to make sense to read LIVE DATA to know WHAT the signal actually IS, and then to check wiring for the Sensor to rule out a fault that will STILL be there if you throw parts.

Attached to NEXT Post is ISTA SSP wiring diagram for High Pressure Fuel System on 3/2011 335i w/N55 engine, with "Lines" ID showing Sensor Signal wire, Yellow/Red, Pin #1 of Connector X6328. I'll also attach the ISTA Screens (2) showing Code Definitions.

INPA & ISTA are FREE downloads. BimmerGeeks K+DCAN Cable to connect to OBD II Socket is $45. Even if you don't already have a Windows 10 Laptop, paying $200 for a 5- to 10-year-old Lenovo will pay for itself in thrown parts and downtime VERY quickly. HOW much did you pay for your phone.

George

[gbalthrop]

Two ISTA ScreenPrints attached per above & Prior Post.
George

[drivetolive]

Thanks for the replies. I've been tackling other maintenance items on other cars that I've neglected to tackle this yet. I will perhaps get knowledgeable on INPA and try diagnosing this in the coming week or two once I have time. Will definitely report back once I find a the issue!

[drivetolive]

FYI for those who encounter similar issues, ended up being the HPFP.

[TunafishE93]

Funny mine just went out in the n55 also.. What replacement pump did you get?

[drivetolive]

Sorry for the delayed response, I ended up with a rebuilt OEM unit.