91 blazer 4.3 tbi timing

trying to get correct precedure on setting time or checking it. had some trouble over summer and a friend set it by ear. now that the problem was solved (weak fuelpump) i want to set it the right way.
i heard there was a wire that needed to be disconnected but not
forsure which one or where.
its 91 s10 blazer 4.3 tbi. thanks for help

I found it on another web site, here's the link
http://s-series.org/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=52&page=1

thanks ill check it out

should it be 0 degree ? sticker missing.

cant find the corrct setting. i do believe it is to be set at o degree,
anyone know?