It sounds like you are not getting the chain tensioner extended. Just to be sure you have the plunger type, correct?
If you get a manual from the library and in there it will tell you to put a screw driver between the tensioner shoe and the plunger then turn and to you suprise the tensioner will pop out. It's almost imposible to get the plunger to come out other wise. I did the same thing, went out and bought a new one b4 I read the book and relized the old one was still good.
good luck, CC