Hi I have a 94 deville and the drivebelt recently came off. I was driving and then I heard a noise coming from the engine along with smoke. I pulled over and checked it, the drive belt had come off and after checking it closer I saw it was because the crankshaft pulley was stuck and wouldnt spin causing the belt to create friction and smoke... Does anybody know what couldve cause it to stop spinning and how I could fix it? Any help would be appreciated. thanks

Alright talked to my friend, he thinks my alternator probably isnt spinning as loose as it should be. Im not sure if the crank pulley should spin but all the others do including the alternator. Could my friend be right about the alternator not spinning right?

The crank pulley doesn't move unless the crank is rotating.
One of the other pulleys is likely responsible.
The water pump is a big suspect on a 4.9, I am assuming that this is what engine you have.
Check all the pulleys for binding and proper alignment.

Yes, it's a 4.9. Did you figure out which accessory is stuck? Is the belt on the engine still? I'd take it off, and find out which pulley isn't moving freely.

yea its a 4.9, and it turned out to be the alternator that wasnt good. I got one from the junkyard for $15 and the car turned on. The old one was worn out/not spinning right I guess...