2011 M3 cylinder 3 misfire code

[linnadawg]

Opinions on my diagnosis?

I had Bmw code 2755 or P2307 for cyl 3 misfire. Swapped coil and misfire stayed on cyl 3. Checked data and fuel trims for both banks were between -22% and -25%. Checked fuel pressure with scan tool and pressure sensor was reporting 58psi at idle. Mitchell says 43.5psi at idle is spec. Around 85psi at startup.

I hooked up a mechanical fuel gauge and pressure was actually at 43psi. On startup the sensor is saying 100psi when it’s actually at 85 psi. Sensor is consistently reporting 15psi too high.

I check wiring to the fuel pressure sensor. Sensor ground has 50mv. Has 5v reference. Signal wire steadily falls as fuel pressure falls.

I believe the fuel pressure sensor is a main input to the computer for determining fuel trims. Pressure sensor is telling the computer pressure is too high so the computer is reacting by severely decreasing injector pulse width. Fuel pressure is actually correct so I think that’s causing a lean misfire on cylinder 3.

These engines are sensitive to picking up misfires because of the ion sensing built into the coils. I had 2 Bmw techs tell me that I don’t have any fuel related codes so I’m wrong. What do you guys think?

[dreamcast731]

Hello OP,

Did you ever figured out what the problem is?

I'm getting the same P2307....

DME Fault Codes
275 ignition cylinder 3 activation
279D Power Management, closed circuit violation

Any help or input would be greatly appreciated!

Thank you!

Kenny