lundi 9 juin 2014

Issue with N46 engine: eccentric shaft/valvetronic?

Hello all,



I'm having a very strange issue with my car that seems to be related to the eccentric shaft sensor and possibly the valvetronic motor. I drive a bmw with the N46 engine (318i - identical setup to the e87 118i).



For the past few days I've been reading up on pretty much every thread related to these parts and systems and am pretty sure of my diagnosis. (Threads such as http://ift.tt/1uJAM7A, I have all read).



So here's my diagnosis:

- Recently I had to add oil to my car after ca. 14k km, so nothing unusual. When pouring in oil, I spilled a bit over the side in the direction of the eccentric shaft sensor

- A few days later after going on an 80km drive, turning the car off and restarting it shortly after, I got the limp mode: engine fault, reduced power.

- At that point I hooked up my laptop and read the fault codes with INPA (fault report below). Codes that were thrown were 2A67 and 2A6B - related to the VVT.

- So I started reading up on the threads and found out about oil leaking in the sensor. So I peeked into the sensor and indeed: oil was inside. Cleaned the sensor out and as soon as I did that, the engine ran smoother than it has ever run since I've got it (1.5 years).

- About 2 weeks later, after the same drive (and some other drives in-between, ca. 100-150 km), I once again got the same fault codes after turning the car off and restarting it shortly after. Again hooked up my laptop and got 2A67 and 2A6B again.

- Peeked in the sensor again and there was a little bit of oil in there, but not that much

- Cleaned it out again and the car ran fine again.

- 1.5 weeks later: I drove approximately 100km in total over that time, and after a 35 km drive, again: same problems. This time however, there was like 1 drip of oil in there but not anything touching the connectors of the sensor, so not enough to cause a problem. So the error stayed. I unplugged and replugged the connector to the eccentric shaft sensor a couple of times and the errors disappeared, so I could drive home without limp mode. At this point I did notice a clear loss of power, especially below 2.5k revs (above that it felt fine but didn't pass 3.5k revs for safety reasons).



To me this sounds like my eccentric shaft sensor went bad due to oil and is slowly dying and probably very close to complete failure.



However, when looking at the error codes thrown by the car I'm starting to slightly doubt this conclusion, because the VVT direction and refence sensor degrees practically add up to 180 degrees. 180 degrees is the number that the sensor adding up are supposed to give because these 2 sensors calculate the angles in opposite directions to verify the position. If the VVT sensors give the right values: how can my sensor be bad? This makes it sound like it's a valvetronic motor issue, while the sensor going bad would be logical considering the oil.



On some other threads I've also read stuff related to vanos solenoids, but this seems a bit illogical to me considering the codes I get.



I'm hoping anyone here could help me shed some light on this problem!



Thanks in advance for your help.



Kind regards,



Martijn





ERROR MEMORY:



2A67 CDKDVEST - VVT-activation

P1050 VVT-Control Circuit (Bank 1)

Error counter: 2

Logistic counter: 40

1. Umweltsatz

Mileage 106640 km

Supply voltage (ub) 11.02 V

based on byte storage for B_vvt in FF- Array (bitcnv_vvt) 1.00

Status Error Overload VVT1 (stdvovrld) 8.00

Voltage Diagnostic-Port VVT- Control (uvvtdia) 1.62 V

2. Umweltsatz

Mileage 106640 km

Supply voltage (ub) 11.12 V

based on byte storage for B_vvt in FF- Array (bitcnv_vvt) 1.00

Status Error Overload VVT1 (stdvovrld) 8.00

Voltage Diagnostic-Port VVT- Control (uvvtdia) 1.62 V

Actuation error general

Test conditions fulfilled

Error present now and already stored

Error would cause a warning lamp to light up

Diagnostic active

Cycle flag set

MIL on

Error code: 2A 67 E8 15 10 50 02 28 34 12 75 01 08 53 34 12

76 01 08 53 FF FF FF FF FF FF

-------------------------------------------------------------

2A6B CDKDVPMN - Power supply limit VVT-emergency

P1062 VVT-Limp Home Request Full Stroke Position not Reached (Bank 1)

Error counter: 1

Logistic counter: 40

Mileage 106640 km

Air mass flow (ml) 20.00 kg/h

Status Error Overload VVT1 (stdvovrld) 8.00

VVT- direction sensor raw value (exwnkfsr_u) 139.92 °

VVT- Reference sensor raw value (exwnkrsr_u) 42.89 °

Valve doesn't open (angle detection), total throw is not reached

Test conditions fulfilled

Error present now and already stored

Error would cause a warning lamp to light up

Diagnostic active

MIL on

Error code: 2A 6B E2 11 10 62 01 28 34 12 05 08 C7 3D FF FF

FF FF FF FF FF FF FF FF FF FF




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