[jimmylomax]

Originally Posted by Weather Spotter

You need to find the wire diagram for your car, each is different. If you have a ECU Pin out ill be happy to look it over with you and help find the wire
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It is a 2008 Honda Fit Sport – same as OP

Originally Posted by Weather Spotter

try this diagram:
Wiring Diagram
you want to add your relay in line with the yellow/black wire after it combines the injectors but before it merges with anything else.

I believe this link which you shared is the correct electrical subsystem schematic

Originally Posted by Weather Spotter

if you look at the diagram posted above, it you cut the wire not in the spot listed you will kill the whole fuel system, not just the injectors. you also kill power to the immobilizer and then need to cycle the ecu. just killing the injectors will not cause the issues listed by vman455.

I think this is probably a wise statement from a wise man


Here is the PCM pinout:
ECU Diagram - Unofficial Honda FIT Forums

edit: and here is the marked up photo I took yesterday showing the intake manifold and injector harness junction where I'm thinking of going Edward Scissor-Hands.