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bmw-mechanic's picture
southwest germany
Joined: 02/25/2014
Posts: 61


i´ve found replacement magnetic vane hall sensors replacement for the bosch hall sensors, build in ~09/1980.

to compare the technical datas, i`ve added the original data sheets of the honeywell 4AV and the bosch sensors.

the administrator of the kleineboxerforum (german r45 and r65) is using these replacement sensors now since ~30tkm without any problems.

order contacts

the admin of the kleineboxerforum allowed me as well to give the link to his repair manual (selfmade).

unfortunately, the document is completely written in german, but the pictures are mostly self explaining, so i`m shure with little skill, every bmw mechanic is able to repair this spark-ignition sensor on his own.
the pictures give you a good illustration what is inside this "magic-Box" and how do dismantle this unit.

another hint from my side, if the idle rpm is sometimes lower 1000 rpm and sometimes up to 1500rpm, check this internal flywheel pre-ignition regulation inside this sensor box. the small retention springs are sometimes damaged or broken. the same thing than the previous mechanic /5 to /7 ignition spark interruptor.

hall sensors are aging over the years with high temperature. the old boxer engine does not produce so much heat to this sensor than the flyingbricks, but these sensor can annoy you whilst bugfixing if the spark ignition does not work properly.
in most cases, the engine starts when it`s cold and if it has operation temperature, the engine spark fails (nearly same behaviour if the spark coils are damaged). then check the spark plug if it is wet. if this is the case

i`ve been using freezing spray and freezed the sensor unit from the outside near the magnetic vane sensor. if the engine then works well, you`ve fixed the bug.



bosch_hall.pdf172.23 KB
p87605_2.pdf470.15 KB