Hope this helps the green wire is from my boost gauge it is an AEM UEGO setup that logs boost vs RPM. I stripped some insulation off of the purple wire, soldered the green wire to it, then put liquid electrical tape over the connection. I wouldn't say I even stripped it, I think I may have used a pair of wire strippers made a cut around the insulation and pulled it back to make room to connected the tachometer wire. After it dried I wrapped it in electrical tape, looks a little like a mess now, removed the tape to get a good picture.
Magnaflo Redline dual exhaust
Werks Turbo @ 10 PSI
KappaSphere coil springs and rebar
ZOK anti-sway bars
DDM Works Latin Venom front brace, Pro Beam, Racing Back Bone