ok so before i changed the Plenum, the belt alwas ligned up. now i noticed this morning when i checked my oil, that the belt was partly off the Idler pulley (1/3 of it not running on pulley)

So i checked for slack it was tight. so i released the slack and aligned it properly. released the tensioner, and pulled it back a bit to get extra tension. I starter the truck, and it immidiatly slid of 1/3 of the way again. Shut it off. No slack at all. Tried moving tensioner by hand, and its tight.

I did take off the Idler pulley to do Plenum...hell its th forth time ive taken it off. never had a problem before. the pulley is not loose, and looking at them they all look ligned up. Its not squeaking or hitting anything, but im scared of what can happen if it does fall off ( falling off towards water pump)

Any help is greatly appriciated

 

are all of the pullets plumb...not just lined up with each but level?

 

your tensioner shouldn't be tight. unless you mean that if you push it toward the drivers side it comes back at you with a good bit of tension.
when you say "pulled it back" it makes me think that it is sticking. mine was like that and i replaced it. when putting the belt back on i would have to pull the tensioner back toward the passenger side to get the belt tight.

i don't know if that would cause the belt to slip off the idler but it should have some spring to it.

 

yea. i mean i took apart the same stuff i did, pulley wise, for the plenum as i did for the water pump. after i did the water pump everything was fine. I always check all my fluids, and connections, hoses etc. every 3-4 days. And it never did this after the water Pump. So its weird that its doing it now.

and by pullets plumb, is that the grooves on the pulleys? if so yes they are all in great shape

 

what i mean by pulling it back is when i released the tension to let it tension iteself, i gave it a firm pull back, no bigger that 1/4in further back.

 

i think he meant plumb in relation to the timing cover. rotate the idler by hand and see if it has any wobble.

 

i misspelled pulley...pullet is a chicken...lol

are the pulleys plumb?

 

none of them are loose. the harmonic balencer has a slight wobble, but not bad at all

 

Are all the pulleys lined up with each other? Depending on what you took off to do the plenum, sometimes the brackets and/or spacers can be reinstalled on the wrong side of bolts and such. And you did loosen or remove the belt to check the pulleys for looseness right?

 

i check for wobbling, first with belt on, then took off belt and saw if any had wobbling. none of them did. and i tried to eye view all the angles i can, and they all line up with each other from waht i can see.