BMW Repair: 1987 325 Hot Starting Issues, spare computer, ohm meter

Question
I have been having this issue for some time and only now has a gotten really bad.  The car (when cold) will start up and run fine.  However after its been running a wile when you shut the car off it will not restart.  After sitting 20 min to an hour it starts up and runs fine.  When its not starting it will still turn over fine.  I checked and when not starting I am not getting any Spark off the coil.  So my guess it would be some kinda electrical issue. (not fuel system which was my first guess until I found that I was getting no spark)
My next test will be to see if I am getting power to the coil.

I have a spare computer for this car. using either one has the same result.  So my guess is that that is not the problem.

Any thoughts or suggestions would be very helpful

Thank You
-Jay K.

Answer
Well the spark is given through a sensor that passes by a pin in the flywheel.It has a grey tie on the sensor and is located in the bell housing. The sensor can be measured with an ohm meter.The terminals with the sensor with the tabs up the pins to the right should read about 540 ohms.I'm sure with it working then not after warm up leads me to think it is that sensor.