I'm still bothered by the shimmed crank pulley. Do you have another that you can try just to see how the belts tracks? Just went out and started mine to check the tensioner. Absolutely no movement and belt tracks perfectly.
In my experience it's not unusual for a serp tensioner in general to walk a little. The springs in 'em get weak and the issue gets worse.
That's not to say this isnt an issue for you - only to say that it can be normal. It seems to me that it would really have to be flopping to affect the alt (the alt has a good wrap-around from the belt as I recall).
Ok thanks guys. I bought another one EXPENSIVE $75! My guess is that between the loose belt, JuMpInG tensioner and locked up idle pulley it was a disaster for belt fly off.
I'll cross my fingers but i have doubts it'll be that simple for u. My tensioner jumps around and thats not even in the "safety" window, it hits the stop on the tensioner meaning the belt is too big, and it could be tighter. Yet it never jumped off. If its still coming off with only the jumping tensioner not fixed then i dont think it'll fix it. Something else must be off.