After kendra and Faith, when buffy dies for the 3 month time how come another slayer is not called to take over buffy, because when buffy died for the 1st time it was only 4 a second....

After her 1st death Buffy was no longer an active slayer. Faith was. New slayer would have been called only if Faith had died.

I think Buffy wasn't on the 'slayer detector' when se died the second time, pity it'd've been good for another to get called

your talking about when Buffy died in the finale for season5. remember Faith was a Slayer and alive, so they had 2 Slayers, when Buffy died it took them down to 1. therefore there was no need to summon a new Slayer because Faith is alive.

After Buffy died. Kendra was called, passing the slayer torch to her. Buffy was no longer active for that magic. When Kendra died, she passed the torch to Faith. Now the only way for there to be a new slayer is if Faith dies. That is until the series finale.