Pontiac Repair: 1989 2.8 l serpentine tension arm, crank shaft, belt tension

Question
My engine died and when I got it started the tension arm jumps forward and kills it again.  Is there a way to adjust it or does it need replacing?  Or could it be bad A/C compressor bearings causing this action?

Answer
Hi Marty:
it could be a lot of things but if the tensioner arm is loose maning it no only moves up and down for the belt tension but inward and outward from the engine it will throw the belt off. The pivot on the tensioners do go bad over time. with the belt off and the engine off spin all of the things the belt drives except for the crank shaft balancer. if any of thme feel really still or real loose or are noisey you would want to look at them as well as the tensioner. good luck :}