Pontiac Repair: 1996 pontiac sunfire gt

Question
its been tuned up recently traveled after trip was about 400 mi. maintained fuel and oil but on last oil it was overfilled so I took about 1 1/2 quarts out it cranks everything turns on but wont start changed the ignition fuses the 20 and 50 now im boosting it but still no luck how do I know if it might be the crank shaft sensor or whats wrong?

Answer
Hi Jenna:

it will not crank (turn over)? it's not a crank shaft sensor. you need to check the "crank" voltage at the purple wire at the starter motor. have someone crank the car and you need check the voltage on that wire at the starter motor. if there is 12 volts on that wire the starter motor assembly is bad if not then you have a bad neutral safety switch on the transmission or a bad ignition switch or if this had an ignition switch relay recall cone on it then it could be the relay that was installed in that recall kit. it's a process of elimination and back tracking from the starter to find where you are loosing the "crank" voltage. out of the ignition switch that ckt. is a yellow wire and it changes at the safety switch on the transmission to purple. good luck :)