Rough idle and loss of power with codes p1344 and p1350 (mysfires)

[jac]

I would appreciate your guidance on troubleshooting this.

I did a bit of reading through some old threads, and also based solely on the direct meaning of the codes, I am thinking I should (in no particular order):

- check the ignition coils and spark plugs (cylinders 2 and 5) --- but I doubt this is going to be the problem since all 6 coils and spark plugs are 1.5 years old or so
- do a vacuum leak test

Am I on the right track?

Thanks!

[andrewwynn]

When wife's m54 had similar code/symptoms ended up being combination of old (weak) coil and dirty injectors.

Traded in a younger coil from a donor car on the first cylinder that gave the error then "whack a mole" started where it just moved to a different coil. Problem went away after a treatment or two of Lucas injector cleaner at double the strength listed on the bottle.

[Effduration]

I had to look up those codes. They are misfire codes. But P-codes are the most basic codes. If you plan to own this car for a while, I suggest you get a better quality scanner and one that reads BMW-specific codes.

I would suspect a vacuum leak first.

you might unplug MAF and see how it starts and runs. You will get a code related to MAF.. But if it runs better, smoother, you most likely have a vacuum leak, which you will find with a smoke test....But don't use the cigar /fluid pump method..not sufficient.

[X5chemist]

Interesting. I would suspect P0302 and P0305 codes for misfires. Yours are start up misfire codes. Check your auxiliary air pump hose. It should start up and run for a few minutes before shutting off at start up.

[jac]

Thank you folks.

Sorry, I only had access to the generic bluetooth code reader at the time I created the post.

I just ran it through INPA and BMW Scanner and those corroborate the "generic" codes from the bluetooth code reader :-).

I also neglected to mention that yesterday when the issue started (I had been driving on the interstate for a few hours), I could smell fuel in the cabin for a bit, so I am thinking the fuel mixture is too rich and therefore maybe a MAF problem?

Also, I just did the test suggested by @Effduration [disconnecting the electrical plug from the MAF while the engine is running] and the engine did seem to stabilize some, though not sure it fully stabilized. I did an audio recording of the test, I will post as soon as I figure out how to get it uploaded to youtube :-)

Next up going to try moving the coils around and see if the issue moves to other cylinders.


INPA report

           E R R O R   M E M O R Y   R E P O R T
           -------------------------------------

Date:      11/20/24 11:23:39
ECU:       MS430DS0
JobStatus: OKAY
Variant:   MS430DS0

-------------------------------------------------------------
RESULT:    2 errors in error memory !
-------------------------------------------------------------

242   Misfire in cylinder (Verbrennungsaussetzer Zylinder) 5
Error frequency : 1
Logistic counter: 40

   TCO                                         92.25  Grad C
   N_32_TOL                                  1120.00  rpm
   MAF_TOL                                    201.54  mg/stk
   MAF_BOL                                     92.60  mg/stk
   Occurred before (aufgetreten vor) (rel. BZ)  2.50  h

   ---
   Misfire CARB_B1
   ---
   ---
   The error is emission's relevant (Fehler ist abgasrelevant)
   Error "debounced" ?? (Fehler entprellt)
   Error currently not present (Fehler momentan nicht vorhanden)
   Sporadic error (sporadischer Fehler)

Errorcode: F2 B2 01 28 BB 23 25 11 35 F5
-------------------------------------------------------------


239   Misfire in cylinder (Verbrennungsaussetzer Zylinder) 2
Error frequency : 2
Logistic counter: 40

   TCO                                         92.25  Grad C
   N_32_TOL                                  1120.00  rpm
   MAF_TOL                                    201.54  mg/stk
   MAF_BOL                                     92.60  mg/stk
   Occurred before (aufgetreten vor) (rel. BZ)  2.50  h

   ---   Misfire CARB_B1
   ---
   ---
   The error is emission's relevant (Fehler ist abgasrelevant)
   Error "debounced" ?? (Fehler entprellt)
   Error currently not present (Fehler momentan nicht vorhanden)
   Sporadic error (sporadischer Fehler)

Errorcode: EF B2 02 28 BB 23 25 11 35 F5
=============================================================

BMW Scanner -> please see attached screenshot below

[jac]

Here is the audio for the MAF unplugging test (please excuse the wind noise).

At 32 seconds into the test, you'll hear the misfires starting to occur, completely on their own.
I unplug the MAF at the 48 second mark and I plug it back in at the 1:34 mark.

Note that the engine was already warm when I did this test.

[jac]

I did the smoke test and found no leaks. I confess I used the cigar method. I had done it once many years ago and found a leak with it back then, but I did not find a leak this time.

As I was doing the test, and capping the system at the top of the boot, just before the MAF, I decided to have a look at the air filter, and I found that I had installed a reusable K&N filter (back in 2019 according to my records). The bottom side of the filter was covered in gunk. It is late now, but tomorrow morning I will go get the K&N cleaning kit and see if that's what's causing the issue.

[workingonit]

Misfires, MAF, and K&N filters....

I only had one or two misfires a couple years ago, and they never returned, but I have been searching for a phantom vacuum leak and/or MAF problem for three years. My M54 has high "lean" fuel trims.

I've smoke tested with a homemade tester several times, then with a good factory built unit, several more times, and found nothing. I also used carb cleaner spray as well.

I can unplug my MAF and it stumbles and stalls, and the cheap MAF I'm using reports accurate GMS/sec, unlike the OEM Siemens (which was wildly inaccurate, the last time I used it).

As for oiled K&N filters: I used to use them on all my vehicles, but stopped a few years ago, because they were affecting the MAF sensors on the newer vehicles. But, I continued to use them on several pickups and my race car, because they were old-school with big V8's, big carburetors, and no pesky MAF sensors.

Sent from my SM-G965U using Tapatalk

[jac]

Back in 2016 the MAF went bad and folks here helped me narrow it down to that. Back then, I first tried using a cheap MAF, and although it seemed to work, other things were acting up. So, I bought a Siemens/VDO MAF and everything was resolved with installing that MAF.

It could be that the MAF is bad again in my case, but I haven't gotten to that point, and I am trying to NOT just throw parts at it yet :-)

I cleaned the air filter and cleared the trouble codes, but I have not been able to go drive it for a bit, I may get sometime to do that tomorrow.

[Effduration]

the cigar smoke test will find a leak in your intake boot, but its not enough to find many other vacuum leaks deeper in the intake, DISA, etc.