i bought a tach from a store. hooked it up the way the directions say and it dont work. Why?

you either hooked it up wrong or its broke

make sure you have it hooked to the blue wire out by your distributor. i have a 1990 civic hb manual and thats where i caught mine at.good luck and i hope this helps you

go to a junk yard and get a si cluster and replace yours with it. it does fit and all of the plugs fit right. mine works just fine and it cost less than a tach