i need to hook my tach up

i dont know if the blue wire in my wheel well is the right one

All the wires should stay inside the car!
http://www.westworld.com/~joe_r/tach/tachinst.html - how to install tach

There should be a blue wire on the driver side. It has a black cap on it it, it is used for diagnostics to find the RPM's, you can hook your tach into this. Let me know if you have anymore questions.