MembersPage/PhatBob/MagnettiMarelliSensorProblem (2015-01-01 07:00:00)

Testing the v3.3 units purchased recently (#316, #317, #328 & #360) with this: http://www.mmcompsys.com/download_zone/6_sensors/SEN.pdf Magnetti Marelli sensor - which is a common sensor used by the likes of Omex and MM themselves. Its resistance was measured at ~620 Ohms.


After Emil's suggestion I took a VR sensor with a 500 Ohm impedence and wired it to the EC36 plug on my bench. Testing on a known working unit (316)I set the primary trigger type to coil and put the sensor on a mains adaptor, it gave a value constant reading of around 1500rpm. One of the suspect units was then tested with the same settings and there was no reading (0000rpm)

We should examine the VR waveform. This depends on the toothwheel (not the sensor: 800 Ohm should not be a problem by itself). If the amplitude at the missing tooth is way too high (max difference between amplitude of any 2 teeth should be < 15%), it is possible that one ECM triggers properly and another not. Obviously, either ECM must trigger OK on a proper-waveform VR signal. Watch wheel-error, since that might be a good indication of this. Do you have a picture of the toothwheel ?