Im just finishing up with a big wire hiding project and my factory tach isnt working properly. I have a MSD 6AL and while the engine cranks the tach appears to work just fine but once started it just reads 0 RPMS. Please help.
Check the voltage, fuel, oil, water guages. If they are dead (they will be floating in the middle) then your #18 fuse went out. That fuse powers the instrument cluster. Won't effect the speedo because it's mechanical.