BMW Repair: 1986es wont start when in the sun, crank sensor, cranks

Question
When the car sits in the sun enough to get hot inside (black car)it cranks but has no ignition spark. Replaced main relay (white one toward front of car and under the black platic cover), no help. Then I replaced the ECU, no help. If I move the car to the shade and open the doors for a few (10) minutes, it starts right up. Whats up? I live in Denver and the car is dry and in excellent condition. Crank Sensor? Ignition Sw? Ideas. Thanks.

Answer
Bob, I have no idea what is wrong with your car and am sorry.  I have never heard of a car not starting from being in the sun, and can't even begin to tell you where to start with that without not being there to look at it.  Try one of the other experts on here, maybe they can be of better assistance to you then i am.  sorry.