my efxr was makeing noises ,found the belt was rubing against belt tensioner,because the crank pully had moved out and today after fireing it up it moved further forward throwing the belt.
has any one ever had this happen ,why does this happen and most important ,how can it be fixed ?

its a reasonably common thing to fail..
sounds like the outer pulley has come away from the centre..
it just happens with age or possable oil contamination
unfortunatly it need to be replaced with a new one..

Yeh it's either come apart as said above, or sheared the bolt in the crank..... highly unlikely though on that one.
I'd recommend not starting it again till you've fixed it =)
May end up needing a new radiator too.

thanks guys,i removed the radiator fans and taped it back in to right position ,but its probably not going to stay .
could bolt be loose ?,the crank turns when i try to tighten it,i guess that meens the bolts not sheared.
radiator's ok .not sure weather to put back together and drive it down to local mechanic,its about 1k away.

If it were me, I wouldn't be driving it. Tape aint gonna hold it in man. Lot of centrifugal force going on when its rotating.

i didnt tape it ,i tapped it back in with a hammer,but your right if i start it up it will probably move staight back out again .whats the easyest way to stop crank from turning,to see if i can tighten it back on ,its an auto ?

If the rubber middle section of the pulley has failed, allowing the outer ring to move forward, the bolt in the centre of the pulley will still be tight and you will be wasting your time. In this case, the only solution is to replace the pulley.

If the whole pulley (including the centre) moves when you tap it back on, the pulley has "walked" off the front of the crank, meaning the bolt must be loose. You should be able to remove the bolt without much trouble, and will need to do so anyway to put sealant on the threads (if for no other reason than to prevent it coming off again).

They can be a devil of a job to tighten with an auto trans. I lost two belts because the crank pulley wasn't fully seated so was out of alignment with the other pulleys. To tighten the bolt, I remove the cover from the lower half of the front of the auto, and jam a large screwdriver or small prybar into the teeth of the flexplate while I tighten the crank bolt using a long bar to get enough leverage. It's a two-person job, but reasonably easy, and I don't know any other way. To get the trans cover off you will need to remove the four bolts holding it on, plus loosen the four bolts holding the aluminium trans braces to the block. After the first time, the whole operation took me about half an hour - and I never rush it.