My brothers 1994 Chevrolet Corsica will not start but when you try to turn it over it will try, but makes a hollow popping noise as it is trying to turn over through the throttle body, where the air filter is hooked up to. We took it to a so called mechanic who said it was the timing so he changes the timing chain and gears, and said the timing was not out. He was on a ride, and the car died, he got it started once, and we haven't been able to get it started again. Would that mean that when the timing gears were replaced, it was that the guy who worked on it did not top dead center the gears and motor?