ya know - a bad coolant temp sensor can and will prevent the car from starting.

The symptom is that it will turn over and turn over but not start, or start after a lot of cranks. The sensor basically determines if the car is warm or hot and adjusts the fuel ratio for starting the car. If it thinks the car is cold when it is warm it will flood the car. If it thinks the car is warm but the car is cold it will not give enough fuel.

This does not appear to be the OP's problem, since he says he sometimes gets no response from the starter at all.

SPhilli911 - ignition clicking really does indicate a bad battery. If you can, switch it out for another battery for a couple days to see if it solves the issue. Clean all the posts on the battery with post cleaner. Check the voltage on your battery wires with a multimeter to make sure they are not bad.

You could have an intermittent bad ground somewhere.

 

Yep, my car does nothing. I think the battery drains.

I was just talking to a buddy who says his father's E34 had a problem similar to mine. Well he told me something interesting... to keep the battery from draining, he had to turn the wheel to the left 90 degrees when parked.

That got me thinking. My car has gone through loads of steering problems (new pump new rack) and I realized that every night I park my car, its with the wheel to the left. But the other night I kept the wheel straight.

Idk... sounds strange, but plausable. Might as well see if that's the issue.