belt comes off the back of the tensioner

[5.0ltrriceeater]

I have deleted the ac and smog pumps and have tried running a short belt. My problem is that the belt wants to roll off the back of the tensioner and hit the aluminum part of it and shred the belt.
I also tried putting a upr smog pump delete pully on there and that doesnt work either.
All my pullies look to be aligned good, and i even put a new tensioner on there.
Im out of ideas to correct this and any info would be freakin awesome!

 

[The Green GT]

Try to put a belt that is like half an inch shorter on. They tend to stretch and slip off sometimes.

 

[Pokageek]

I have deleted the ac and smog pumps and have tried running a short belt. My problem is that the belt wants to roll off the back of the tensioner and hit the aluminum part of it and shred the belt.
I also tried putting a upr smog pump delete pully on there and that doesnt work either.
All my pullies look to be aligned good, and i even put a new tensioner on there.
Im out of ideas to correct this and any info would be freakin awesome!

I just found this. Sorry I created a whole nother thread on it but I thought I''d try and ask if you figured this out? Was your belt too loose? was it a bad bearing in one of the idler pulleys? This happened to me tonight. My belt was rolled behind the tensioner pulley just like yours and tore all to hell.