so what should i do if i pulled the pin on the tensioner before install?
do i need a new one or can it still be dont with it already opend?

 

Put the pin back in.

 

i cant push it back down to get the pin back in i tryed that.

 

First off why did you pull the pin? Anyway compress it in a vise and put the pin back in. Or since I have no what tensioner you are talking about serp or timing ( I am assuming timing) you can install and use the wheel to compress it, then put in the pin