My 91 945 turbo won't start. It appears not to be getting spark. In checking the resistance of the RPM sensor, I get 170 ohms from the center terminal of the cable to one outside terminal, and an open circuit from the center to the other outside. Should I get resistance for both readings, and if so, do my readings mean the sensor is bad? In following direction from this forum and the shop manual(much more detailed info heer than in the Chilton's book), I have replaced the ignition control module on the sidewall near the battery, and I now have a new coil. It stopped running, and hasn't started since a week ago. Thanks for your usual help!