Great comment. I recommend to anyone with cranking problems to use a voltmeter to measure voltage drop from the engine block to the battery negative terminal. It has been several years since I repaired a German car with a cranking problem, but I remember that I had about 2 volts drop across one crimped fitting on a braided ground strap. Once I repaired that connection, the car started great until it was destroyed when rear ended. I can't remember the figure for acceptable voltage drop, but the lower the better. For reference, check a car which cranks well.