[Table8]

Hi all, I have a 2014 F30 335xi with the N55 motor. I’ve been having random misfires and lumpy idle on cold start and the car has been throwing a bad MAF code. I’ve cleaned it and replaced it, but it quickly returns even with a brand new MAF. I was changing the sensor once again today, and took a closer look at the MAF connector on the harness side and realized there are five pins on the MAF sensor, but the harness connector side only has four visible metal connections. See the attached pic and notice that the hole that is 2nd from the left doesn’t have a visible metal connector. Would somebody else with an N55 be willing to unplug their MAF and let me know if your connector is the same or if I should have visible metal pins in all of the five holes? Thank you!

https://ibb.co/0qbhZgW

[COKen]

Originally Posted by Table8

Hi all, I have a 2014 F30 335xi with the N55 motor. I’ve been having random misfires and lumpy idle on cold start and the car has been throwing a bad MAF code. I’ve cleaned it and replaced it, but it quickly returns even with a brand new MAF. I was changing the sensor once again today, and took a closer look at the MAF connector on the harness side and realized there are five pins on the MAF sensor, but the harness connector side only has four visible metal connections. See the attached pic and notice that the hole that is 2nd from the left doesn’t have a visible metal connector. Would somebody else with an N55 be willing to unplug their MAF and let me know if your connector is the same or if I should have visible metal pins in all of the five holes? Thank you!

https://ibb.co/0qbhZgW

My 435i with N55 MAF connector looks just like that.

Have you checked for a vacuum leak?

[Table8]

I haven’t checked for vacuum leaks. The code I get is P00BD which is related to a bad sensor or issue within the MAF circuit. Any tips on common points for leaks? I had the charge pipe replaced with a metal one two years ago and have periodically gone through and tightened up the couplers on that, but otherwise everything looks connected properly. I have the stock intake so I’ve never messed with those connections. Are there vacuum lines somewhere that could have detached or have a hole?

[thejeremyman9]

Stock aside from CP?

[Table8]

Originally Posted by thejeremyman9

Stock aside from CP?

Yes, totally stock. The rough idle and misfires come after the car has been driven up to temperature, and then parked and cooled down, and then driven again. Like if I go to work, park for a few hours, then get back in and drive to lunch. The engine will usually rev really high and then have a lumpy idle for like 15 seconds, like a muscle car with a really aggressive cam lobe. Then it’ll smooth out and the idle will stabilize at around 900rpm or so. Strangely, the check engine light doesn’t turn on during those rough idles, it has come on randomly and intermittently as I’m driving. The light has also turned itself off without clearing codes as well, but I have a scanner and when I check codes it’s always P00BD.

I’ve changed vanos sensors, O2 sensors, and now the MAF. I also have a TMAP sensor for the charge pipe that I haven’t installed yet, so I’m getting pretty stumped.

[thejeremyman9]

Originally Posted by Table8

Yes, totally stock. The rough idle and misfires come after the car has been driven up to temperature, and then parked and cooled down, and then driven again. Like if I go to work, park for a few hours, then get back in and drive to lunch. The engine will usually rev really high and then have a lumpy idle for like 15 seconds, like a muscle car with a really aggressive cam lobe. Then it’ll smooth out and the idle will stabilize at around 900rpm or so. Strangely, the check engine light doesn’t turn on during those rough idles, it has come on randomly and intermittently as I’m driving. The light has also turned itself off without clearing codes as well, but I have a scanner and when I check codes it’s always P00BD.

I’ve changed vanos sensors, O2 sensors, and now the MAF. I also have a TMAP sensor for the charge pipe that I haven’t installed yet, so I’m getting pretty stumped.

Did you trace the MAF wires? I can't recall if that's the one that gets pinched by the engine cover

[Table8]

Originally Posted by thejeremyman9

Did you trace the MAF wires? I can't recall if that's the one that gets pinched by the engine cover

Yea everything looks good. Which is why I was curious if the connecting harness to the MAF sensor looked ok in my pic since four of the five holes have visible metal connectors and one seems to be empty. Thought maybe I needed to replace the connector or fix that pin.

Anybody else with an N55 who can visibly confirm if my connecting harness is ok?