I am sure this has been covered a million times and I've researched extensively but cannot get a clear answer. Where can I tap into to get a 12v constant under the hood for the external coil yellow wire?

 

 

Do you mean a "12v+ switched" wire or "constant" as you stated ??? Constant would have power on it even when the vehicle is switched off.

If you are removing the factory external coil and either installing an internal coil or an aftermarket external coil (like a MSD blaster etc.), simply connect the large yellow wire and the large black/yellow wires together at the OE external coil plug... and tap into this newly formed 12v+ wire if you are using an external coil. The green wire coming out of the distributor would be your coil trigger wire. If you are adding the internal coil, open up the distributor and remove the green wire from the ICM and replace it with a white/blue ICM wire from any internal coil Honda distributor... like a Civic or Integra. Also, connect the yellow/black wire from the ICM to the (+) side of the internal coil. You will have to "T" into the original wire.

 

I figured it out, I was simply wiring an external coil & dizzy from the H22a1 engine into the obd2 ek engine harness. I just capped the black/yellow from the external coil, and spliced the thick yellow into the black/yellow from the distributor. I actually fired the car up for the first time last night, and it runs good. I still have to finish up some things like shift linkage and passenger side axle once my seal comes in, but so far so good.