E30 M50nv swapped, no start condition and solution
Since you E36 guys have the largest number of m50's I thought I'd throw a scenario at you that I very recently had to deal with.
My car has an M50NV out of a "92 325is to be specific.
The car ran a week or so before I had went to start it the other day and this time all I heard click on was the main DME relay. I thought it was weird, but said to myself I'll start it anyways(or tried to). It would crank and crank for days but no action. The fuel pump relay would not click on and after testing it with the multimeter I determined that there was no signal coming from the DME to turn on. I checked the main DME relay for faults, but the relay was good. So I pulled the DME of of its connector (after disconnecting the battery) and started to check for proper resistance through each sensor. The first one I checked was the Crank Pos. Sensor and no resistance was shown. I went on the check all other sensors and they all showed the be good. Found pin locations from the Bentley manual. So I took off my intake boot, disconnected the CPS and checked the wires running from the DME to the connector to make sure I didn't have a broken wire. The wires were good and I now went to check the sensor right off of its 3 prong connector (check resistance across pins 1 and 2) and still got nothing. I had no spark, no injector pulse and the fuel wasn't coming to the rail.
I went to the local parts store bought a CPS made by MEHLE for $95 after tax, put the sensor in and she fired up right away. This sensor showed just under 700 Ohms resistance.
Hopefully this will help someone on here that's pulling their hair out from this same issue.
1987 325is(Midnight Tuning Tuned OBD I S52
) - Current Summer Car
2012 Hyundai Veloster Tech- Daily Driver
1985 318i - 1st Car (started it all)