The engine is a bmw s50b32 converted to single vanos on intake with a trigger with one tooth installed at ~60 degree before missing tooth, the vems trigger log also shows this.

The ecu is unit 7148, vr vr and 4 pfet for vanos control

The car runs perfect in wasted spark mode. Is making 806hp at 7700rpm and 1.5bar boost. Now I'm trying to make vanos work on intake so I can make boost faster, now I see 1bar at 5000rpm.

Vanos is working good from the logs I made but I have problems with the secondary trigger.

When cranking the signal is very good and stable, the problem is when I start the engine. I have to many sectrig and I can't rev past 1300 (similar is the symptom when VR is reversed), the ecu seams to reset as the afterstart flag comes on.

I tried to play with the filter settings (minimum angle 39, maximum 120) and i manage to filter it a little and now i receive only sectrig pos bad and the engine revs, as you can se in the logs at ~4000+rev the trigger error is gone!!!

I made the following:

- Changed the sectrig wiring, completely separate from the engine wiring, from the sensor strait to the ecu, Same result

- Changed the polarity of the sectrig. the signal moved to the second tooth after the missing tooth and the logs shows ~350 degrees. This was wrong because the trigger was installed at ~60 ( 9 tooth before missing tooth )... anyway with the polarity change same sectrig errors

Don't set VR polarity according to position. Just set the right GenBoard/Manual/VrSensor/Polarity

- I changed the vems ecu with a similar one ( vr vr ). same result

- I tried and pull the sensor out ~1mm and got less errors and manage to rev the engine to ~2500rpm with no filters , if i try to pull the sensor more than 1mm the sectrig signal is gone.

- I started with firmware 1.1.96, with this firmware the car worked for a few years with the old ecu without the pfets. Now i have firmware 1.2.11

I will try to look again at the wiring, grounds and maybe rewire the crank and cam triggers!!!

Please let me know if you have any ideas

trigger logs:

I manage to install another vr sensor ( crank sensor from a Maserati Quattroporte) it has 900ohm and seems that it works good. Only a sectrig bad flag right when the engine starts and when I rev from idle. This is with no filters.

Original sensor scopeshot:


Maserati sensor scopeshot:


Positive pulse should be followed by negative pulse (triggering happens at the zero-crossing negative-going edge), so these show Reverse polarity. Also, the amplitude of oscillations (child teeth ?) after the pulse are insane !

Is the large pulse appr 10 teeth after the primtrig missing tooth ? (if yes, than secignore=16, that is ignore sectrig after tooth22 could be useful)...

So the basic question remains:

I was to the dyno a few days ago and tuned the engine. The vanos is working nice, the cam has very good response and is on target all the time...

The black graph is with the setup I had before and the red graph is with vanos, 100 octane pump gas and same boost.

Official is most powerful BMW in Romania :)