How to wire the tachometer

I assume you mean the horn. This sounds like a wiring problem. You may have a wire that has lost the insulation, either by rubbing or by rodents. When you go around a corner, the wire shorts to either another wire or come grounded metal which sets off the horn.

there are two wire beside the injection pump,,,, i think face the injection punp it is leftside... that's the wire sensore to the tachometer

The most common reason for the failure of tachometer on 93 Subaru Legacy is related to the connection of ground wire. Ensure that the ground wire has not become faulty because of wear or corrosion. In case the wire is not functional, it will need to be replaced without which the tachometer circuit will not be complete.

The "Green" wire from the tachometer should be attached to the negative side of the ignition coil only, and usually (but not always) it is a black wire with a white stripe or it is a solid white wire that will come off from the negative side of the ignition coil and often has a tab on the wire that says "Test" or "Tach" and the wire ends with an open black connector that is used for connecting a diagnostic device or tachometer for diagnostic purposes, and this is the wire that the green wire from the after-market tachometer should attach to. The "Red" wire should be attached to an "ignition" source connection on the fuse panel and have battery power when the key is in the "Run" position only, the "Yellow" or "White" wire should be connected to the "LPS" source on the fuse panel, and the "Black" wire should be connected to a good ground source and if the tachometer is not properly grounded then you will get a primary voltage shock from the ignition coil every time that you touch something metal inside of the vehicle. Let me know if you require any further assistance.

there is not a wire!the tachometer is electronic.you need replace the vss[vehicle speed sensor].lift the car and you find it under the exchaust pipes on the gearbox.go to someone who knows isnt so easy to change it1

Go to the autogauge web site they might have a free downloadable instruction on pdf or html.

Tachometer Wire Negative Wire (-): Any Wire That Is Note Red/Light Green. The diesel tach wire is a green/white wire, located in a 5-pin harness held up with tape behind the parking brake release.
Tachometer Wire Negative Wire Location: At Igniton Coils

According to wiring diagrams online... good luck with this.
KEn

the signal wire is coming from the distributor under the hood run the wire through the fire wall to that wire and as 4 the wire that lights up the tach piggyback that wire off of the cigarette lighter on the fuse box

the green wire should be on a pulse wire from the distributor, not the coil

purple/white off the ignition module is your tach signal