Related to BMW M52 MembersPage/BmwMFiftyTwo
important: BMW M52 Camshaft HALL sensor needs to be replaced !
- Cam Sensor with normal LOW/HIGH voltage output must be used to get sectrig
- open collector type, that pulls to GND (=capable to "sink 2mA current")
- that is the standard in automotive engines anyway for HALL or optical type sensors
- 0/5V or 0/12V output is also good
A camshaft sensor that is known to work and easy to bolt on:
BMW 12 14 1 438 081 - HALL Effect Falling Edge.
Pinout (from 1993 BMW .. .pdf document page#106 (m50 vanos)
which we know works (is this a simple bolt-on replacement ?)
- 1) power_supply+ BMW88/pin65
- 2) signal OUT (middle pin on the replacement HALL sensor connector) BMW88/pin64
- 3) ground (eg. BMW88/pin43)
Even though LOW/HIGH cam output can be provided with many methods BMW 12 14 1 438 081 HALL Effect Falling Edge sensor (eg from BMW M50 Vanos) has several advantages:
- mechanical fit (special mechanical adjustments like washer/grinding for axial adjusment should NOT be needed)
- pinout matches the connector, so swapping of pins should NOT be needed
- known to work (from experience)
Measure HALL trigger supply voltage
Related to:
- BMW88/48 primtrig HALL crank sensor +supply
- BMW88/65 sectrig HALL cam sensor +supply for the replacement sensor
- Serialnr
- Vemslog captured with VemsTune during the cranking attempt could reveal something (eg. it would be awesome if only some configuration adjustment would be needed).
However, for trigger problems more measurements are almost always needed also:
- Measuring triggers, DC and AC voltage
- OscilloScope the trigger signal might be necessary
- InputTrigger/TriggerLog
- this might reveal that signal is missing from only primary or only secondary HALL sensor (or both).
Preferrably create custom page for the project (but editing this page to provide information is temporarily OK, possible to organize later, just define some project nickname ).
Old harness
We have a 6cyl BMW harness with 4 connectors of female 3-pin injector (AMP), that was believed to be from M52 (but not certain, but apparently yes) :
TPS
- mot88/42 (TPS GND or shield ???)
- mot88/12 TPS signal (EC36/1)
- mot88/44 +5V for TPS
primtrig HALL: Crank sensor
- mot88/48 Crank sensor +5V
- mot88/83 Crank sensor signal (EC36/27)
- mot88/40 Crank sensor GND (EC36/26)
sectrig HALL: CAM sensor
- mot88/65 CAM sensor 12V ( diode to ->|- mot88/54 might be undesirable ??)
- mot88/64 CAM sensor signal HALL EC36/13
- mot88/43 GND
Idle Valve
- mot88/27 Idle (INJ-H with low voltage flyback)
- mot88/54 DME relay out 12V (this is NOT camsensor 12V as in the errenous doc)
- measured on the floor, ripped out from car
- Dave: pin54 connected to idle middle pin could be correct. mot88/54 comes from DME relay back to ECU (so DME relay switched +12V) also goes to middle
- mot88/53 Idle (INJ-G with low voltage flyback)
https://photos.app.goo.gl/vT76gkVCSKQoLUZS8
Maybe this is from some other harness, not M52 ?
- maybe M60 (didn't check just blind guessing)
- apparently perfectly matches the "M52" harness in the car with ECU Siemens DME MS41.0 (5WK9 0321)
M52 Test bench
Planned: M52 harness from E39 manual transmission
Acquiring a harness from E39 for more tests.
Conclusion:
- got mislead by information (from previous install from a customer - successful VEMS install, but with EC36) "BMW uses 12V HALL sensor supply"
- it seems we (the ECU) must simply supply 5V for TPS and the HALL sensors: pins 44,48,65 and leave pin54 open
- (instead of the traditional +5V), +12V supply (even through a diode, to prevent unintentionally powering the ECU back from mot88/54) for HALL sensors might NOT be a good idea in this setup. Actually, depends on the replacement sensor. BMW 12 14 1 438 081 is best with 12V or 5V supply ?
- of course, activating the DME relay (mot88/73 to GND) still needed. but even activating that (with ignition on) does not provide + supply for HALL sensors (verified on real car in factory harness+setup). So HALL supply becomes simpler actually.
Also see: