My 1996 Chevy Cavalier 2.2 keeps stalling while driving. Try to start and it won't start (No Spark) and the Fuel Pump has no hum. Leave it sit for hours, go back and it will start.

Hmm this is an interesting answer. One of my friends was thinking it could be related to my Anti-Theft System, as my theft system will shut down both fuel and spark. Since this is the outcome when it shuts down while driving. Any comment on this possibility? I will tell him about the cam shaft sensor and the crank shaft sensor. Funny thing is he called me back right after I posted this question. Thanks for your answer Terry. Hmm this is an interesting answer. One of my friends was thinking it could be related to my Anti-Theft System, as my theft system will shut down both fuel and spark. Since this is the outcome when it shuts down while driving. Any comment on this possibility? I will tell him about the cam shaft sensor and the crank shaft sensor. Funny thing is he called me back right after I posted this question. Thanks for your answer Terry.

I doubt that the anti-theft system system would kick in at such a time, but I guess it's not out of the question. With respect to the spark/fuel issue, once the crank sensor stops sending signals to the PCM, it will immediately cut off the fuel injectors, followed quicjkly by the fuel pump. When you attempt restart, you should get the fuel pump prime cycle, but unless there are crank sensors pulse being sent while cranking, the injectors wont work and the fuel pump will not cycle on full time since the vehicle doesnt start. I doubt that the anti-theft system system would kick in at such a time, but I guess it's not out of the question. With respect to the spark/fuel issue, once the crank sensor stops sending signals to the PCM, it will immediately cut off the fuel injectors, followed quicjkly by the fuel pump. When you attempt restart, you should get the fuel pump prime cycle, but unless there are crank sensors pulse being sent while cranking, the injectors wont work and the fuel pump will not cycle on full time since the vehicle doesnt start.

Oops, forgot....without crank sensor pulses, the PCM cannot sync spark to the piston position, so that shuts off as well. I had a 97 Cavalier. It never failed a crank sensor, but my 99 Dakota did. The spark/injection systems are similar on most vehicles. The Dakota had a distributor cap/rotor, so I had a pickup unit instead of a cam sensor, but I did have the crank sensor. Oops, forgot....without crank sensor pulses, the PCM cannot sync spark to the piston position, so that shuts off as well. I had a 97 Cavalier. It never failed a crank sensor, but my 99 Dakota did. The spark/injection systems are similar on most vehicles. The Dakota had a distributor cap/rotor, so I had a pickup unit instead of a cam sensor, but I did have the crank sensor.

But if it were the crank position sensor wouldn't it run rough like it was missing? My car runs smooth and just shuts down and all I explained in my original post. But if it were the crank position sensor wouldn't it run rough like it was missing? My car runs smooth and just shuts down and all I explained in my original post.

The crank position sensor detects the position of the crankshaft and sends synchronization pulses to the ECM. The ECM uses those pulses to know where the crank is and thus where the pistons are. The ECM can them determine when to fire the fuel injectors for each cyliner and when to fire the spark for each plug. What happens when crank sensors fail, it they stop sending the pulses to the ECM. The ECM cannot determine where the crank is, so it shuts off fuel and spark. Dead car - instantly. The sensors tend to go bad intermittently at first, giving you short breakdown period that allow you to restart after minutes or hours of waiting. After while, they just quit altogether. The crank position sensor detects the position of the crankshaft and sends synchronization pulses to the ECM. The ECM uses those pulses to know where the crank is and thus where the pistons are. The ECM can them determine when to fire the fuel injectors for each cyliner and when to fire the spark for each plug. What happens when crank sensors fail, it they stop sending the pulses to the ECM. The ECM cannot determine where the crank is, so it shuts off fuel and spark. Dead car - instantly. The sensors tend to go bad intermittently at first, giving you short breakdown period that allow you to restart after minutes or hours of waiting. After while, they just quit altogether.