Timing belt replacement and subsequent noise (humming)

Hi,
I replaced my timing belt on my Elantra 2003, at the same time i also
replaced the idler pulley and tensioner. The job gone well but i can
hear a noise that was not present before the job was done. I also
replaced my timing belt on my previous car that was an Accent 2004,
and the same sound appeard after the replacement.
What are the most common causes for this kind of noise? Is it normal
for a new timing belt, or did i put too much tension on the belt (too
much tighten) ?

Thanks for you help!

 

Missing any wrenches or sockets?

 

There'll be a whining noise if the belt tension is excessive. I find
it very odd this would occur on the Accent, since it has a spring-
loaded tensioner which will self-tension properly if its mounting
bolts left loose and then tightened after the tensioner positions
itself when all the slack is on the tensioner side of the belt.

 

There'll be a whining noise if the belt tension is excessive.  I find

The problem actually was on the Elantra, yesterday i reduced the
tension on the belt and the problem is solved. There is still a small
whining noise but it's in the normal range.

Thanks for your help.