2011 X5 35i N55 - intermittent starting + CEL on WOT

[bmwannabe]

Hi everyone,


over last few months, my 2011 X5 35i (02/2010 build ) has random starting issues.


here is a video of what I'm taking about


https://youtube.com/shorts/WD_dNzbikjo?feature=share


I also seem to get the half CEL issue on WOT - or above a certain speed. Not sure if the above are related.


I pulled some codes using INPA and here is what I'm seeing

2E0F
2DCE

I know I have issues with the valvetronic which is the cause of the above 2- but I'm not about to replace the ValveTronic motor + sensor and the camshaft on this car.

What I DO want to uncover is the reason why the car fails to start every once in a while. Usually when it fails to start and i leave it for long enough it will eventually start up.

Last time this happened I had it battery boosted and it started right up. Then I took it home and charged the battery for 4-5 hours. Does this mean the battery is on its way out? any way to check this hypothesis? I replaced the battery about 2.5 years ago.


Also got this code

2C57 - Charging pressure control, plausibility Pressure too low.

Fix for above seems to be to replacing the pressure converter:
Genuine BMW - 11747626351 - Pneumatic Wastegate Actuator.


Has anyone done this on an X5 before?

[ard]

Originally Posted by bmwannabe

... I'm not about to replace the ValveTronic motor + sensor and the camshaft on this car.

Good luck with this.


Asking people 'how do I halfway fix a car' is always a mess

[bmwannabe]

Originally Posted by ard

Good luck with this.


Asking people 'how do I halfway fix a car' is always a mess

I pick my battles perhaps with a different mindset. at 11+ years old these cars are far from perfect - and thus far I fail to see a direct correlation between the car intermittently not starting, and the valvetronic issue that is present ( not saying there is 0 correlation as i know there is a DME firmware update that impacts the off position of the valvetronic and helps with starting) - so I suspect this issue is elsewhere.


Battery was replaced about 2.5 years ago. HPFP and Valve cover gasket + valve cover were replaced within the last year. Also repaired a snapped starter ground wire that caused a similar issue a few months ago.


I've narrowed it down to:

1. Wastegate actuator ( boost solenoid ) due to 2C57
2. failing battery or alternator.

open to suggestions


TIA

[ard]

I cannot see how a wastegate impacts starting.


I wonder if the valvetronic is supposed to 'park' itself at a specific location at shutdown, perhaps?
I dont have a gasser, so dunno. It is pretty common for people to damage the VTmotor when replacing the valvecover.


My 19 year old M5 (235k) is pretty much perfect.... an indulgence I guess, but if something breaks it gets fixed.

[bmwannabe]

Originally Posted by ard

I cannot see how a wastegate impacts starting.


I wonder if the valvetronic is supposed to 'park' itself at a specific location at shutdown, perhaps?
I dont have a gasser, so dunno. It is pretty common for people to damage the VTmotor when replacing the valvecover.


My 19 year old M5 (235k) is pretty much perfect.... an indulgence I guess, but if something breaks it gets fixed.

Valvetronic park position has changed with updated DME firmware so this may well impact starting.

Agree that the boost solenoid should not impact starting - this is more to combat the intermittent CEL on WOT ( goes away after turn car on/off )

so I'm looking at 2 potential issues. I will also add possible fuel system sensors to the list of issues.

And yes. I too put my 2002 M3 6MT Coupe on a pedestal - before it was stolen . The X5 doesn't deserve the same status

[bmwannabe]

update: I might have resolved the 2C57 error


2C57 - Charging pressure control, plausibility Pressure too low - happens at high boost / or WOT.


I suspected this to be the boost solenoid - but I found the long braided vacuum line disconnected from the solenoid and plugged it back in. After this I drove it pretty heavily and didn't see any CEL on during WOT.


This still leaves the intermittent failure to turn on which also happened again today. Here are all the codes along with my comments ( most don't come back after clearing )


2BEB - Mixture control: Fuel-air mixture too rich,large deviation.
2E0F - Valvetronic deactivation (DME update might fix)- https://www.babybmw.net/threads/2e0f.../#post-1372272
2D42 - 2D42 - Valvetronic, adjustment range: stop not learned - https://www.bimmerfest.com/threads/2...e-n55.1411776/
2DCE- Valvetronic isn't functioning as expected, but the DME doesn't exactly know why
2E0F- Instances of 2DCE have occured enough times that the DME disabled Valvetronic and enabled throttle body control
2DCF- No Movement Identified in Valvetronic - could be DME or Harness

2EFE - Misfire - several cylinders damaging to catalytic converter or damaging exhaust gas
2F03 - Misfire - cylinder 5
2EE0 - Combustion misfiring several cylinders - Fuel Injection Deactivation
2EFF- Cylinder 1 Misfire Detected 2EE0 - Combustion misfiring. several cylinders: Fuel injection deactivation
2EE4 - Combustion misfiring, cylinder 1: Fuel injection deactivation
2EF1 - Combustion misfiring, cylinder 5: Fuel injection deactivation
2F00 - Cylinder 2 Misfire Detected
2EE7 - Combustion misfiring, cylinder 2: Fuel injection deactivation


2C57 - Charging pressure control, plausibility Pressure too low ( Happens when on WOT ) Vacuum pipe was unplugged

A10A - Exclamation mark on dash ( TPMS? ) ( battery voltage too low ? )



Links above are to E90 335i with the N55 engine and my findings are quite similar.

[ard]

How have you ruled out the actual valvetronic motor being bad?

[bmwannabe]

Originally Posted by ard

How have you ruled out the actual valvetronic motor being bad?

I can't confirm 100% that the valvetronic motor is in perfect working order - but I did perform the following

1) clear all codes and rescan.
2EOF
2DE3 -valvetronic servomotor,activation, volt phase: line disconnection

2) Pulled the VVT connection from valve cover - cleared codes and re-scanned
2EOF
2DE3
2DD6 Valvetronic servomotor, position sensors: Shortcircuit or line break (open circuit)

3) Cleaned both end of the connector ( wiring harness + VVT connector pins) with electrical contact cleaner and re-seated the connection and rescanned
2EOF only.

so its looks like the connection was dirty. Note the 2EOF looks like is common issue and can be cleared after updating DME firmware

After the above - using INPA I ran through the VVT control checks ( 0%, 25%, 50%, 75%, 100% lift position on the cams ) and the requested positions and sensed positions match on each of the above

Following this i cleared all the learned adaptations using INPA. I have yet to do the re-learn but it looks like after this the car starts up fine.

Again - I'm not ruling out that valvetronic may be on its way out - as its a common issue im seeing on other 2011 N55 engines.

This is a pretty detailed video of the VVT replacement fixing the no-start issue on an N55 engine. ( 3 part video series )
https://www.youtube.com/watch?v=5DyCrTElGVs

[SB1120]

For wastegate- the vacuum reservoir is built into the valve cover. Test it to see if it holds vacuum. Plug the source (13-14mm barb near front right corner where nylon hose connects). Plug one of the small 6mm barbs. Connect a vac pump/gauge to the other barb, pull a vacuum and see if it holds. If it’s cracked, you’ll have to replace the valve cover.

For the valvetronic code, line disconnection and no start- if the valvetronic shaft is on the “closed” stop, the intake valves are fully closed and the engine will not fire. The servomotor can fail, harness can have poor connection or oil wicking via valvetronic motor connection OR in my case, the DME can fail altogether. My 12 gave no warnings. Just died one day while driving. That was at about 140k in 2017. I replaced the valvetronic motor with the valve cover in 2020 around 183k and that was a huge headache because I had to do the whole job again with a new eccentric shaft, needle bearings and bearing shells. The original shaft, bearings and servomotor wear together. Once disturbed to install the motor, the old shaft was slightly binding and the motor control is very sensitive. It felt totally fine to me, manually moving the shaft but to the motor and controller something was wrong. ~1500 later and a couple lost weekends, my x5 was back to life. Sharing just to warn you, if you have this repair completed in the future, plan for all of the above and it’s recommended to do the harness at the same time. $$$!

[ard]

For wastegate- the vacuum reservoir is built into the valve cover.

Im not sure I ever heard that before....