How-to Guide: Connecting Tach Adapter to Dodge Hemi

This article outlines a guideline for connecting a tach adapter to a Dodge Hemi with coil per cylinder ignition. The picture shows you the close-up view of wiring connection after installation.

1. Inspect the wiring and the wire colors at each of the coil packs. The same wire at every coil is the power supply of the coil.
2. You will need to cut the power wire in half at each coil on one bank of coils and choose whether to use the left or the right bank. Leave enough wire to splice onto later (2 inches works well)
3. After cutting all 4 coil powers, use a 16g wire and link all the power (harness side) cut halves together, then hook to the solid red of the 9117 tachometer adapter.
4. Use 16g wire and link all the coil-side cut halves together and hook to the red wire with a green stripe of the 9117 tachometer adapter.
5. Ground the black 9117 adapter wire.
6. The gray wire is your new tachometer signal wire.
7. Set your tachometer as 8 cylinder (4 ppr).
8. All connections should be properly soldered and heat shrunk.

(source: http://www.autometer.com/download_instruction/0561B.pdf)