My belt is jumping off track. As soon as I start the car, the belt will jump off the crank pulley about 3 grooves. The belt isn't too loose, or too tight so that's not the problem. The s/c pulley is all the way back where it is supposed to be, and I don't know what to check next!

 

is this a new problem - I mean, has it been working fine for a while and this just started up or did you make some type of change and now it's falling off?

I'd make sute the two pullies are lined up on the same plane, ensure that the pullies are true and not on warped axels and try changing the belt

 

I got the problem solved, something simple of course! Thanks for the replies