Fuel Pressure problems

[RyansBMW]

My dad has a 2010 E60 535xi with the MHD Stage 1 tune on it. Its been having some fuel pressure problems lately. In the past few weeks, the car will completely shut off on him while driving around town. He's able to start right back up again like nothing was wrong. I had him pull the codes and he had the following.


Active:
29DC- DME; Cylinder Injection Cutout
29F2- DME; Fuel High pressure System, Fuel pressure


Shadow:
2AAE- DMW; Fuel Pump
2FCA- Fuel High Pressure ( followed by a bunch of german)
2FDA- Fuel High Pressure ( followed by a bunch of german)

2FDB- Fuel High Pressure ( followed by a bunch of german)

I had him do a 3rd gear pull (he did it in 2nd by accident) and heres the data he sent me
https://datazap.me/u/ryansbmw/2010-5...g=0&data=11-20

Im going to have him do a few more pulls in 3rd gear and make sure the results are consistent but does anyone have a clue as to what the problem may be? The codes point to HPFP but the data shows the pressure to be fine. Im looking at the the LPFP and the lull it goes thru between 3800 and 6000rpm but im not sure how its supposed to act.

[RyansBMW]

Well in case anyone was wondering, the HPFP was the problem. While getting ready to do a few more 3rd gear pulls, the car shut down again and wouldn’t start for 45min. Got it started and went straight to the dealer and they confirmed it was the pump. Replaced for free under the recall.

[AeroGrp]

If the problem comes back, consider that the LPFP EKP module may be overheating in warm weather. Since the HPFP is mechanical, I'd be surprised that sitting around for a bit would make it work again. On the other hand, when the EKP overheats, it shuts the LPFP down and makes it look like the HPFP is bad. My indy was convinced it was the HPFP when my car started doing that once the weather warmed up (contrary to my thoughts and after replacing the LPFP), but the dealer replaced the EKP and I've had no problems this summer. BMW revised the unit (my car had a V2 unit that was replaced with a V3). There is a detailed thread somewhere with a complete teardown of the units to show the differences and why the originals fail.