We where driving my car when it suddenly stopped and would not turn on. Car had a bad mass air flow sensor for a while. When I try to start the car it only makes a click sound. We connected the battery to another car to charge for a while and would not start. I also got under the car and tapped the starter to see if it did anything. I also checked the starter relay and it appears to be fine. My question is what could be the reason my car won't start. It doesn't crank either.