Solenoid to EFI on/off signal wire

If I were you I'd get ahold of DionQ on here. I would NOT use that device at all, because it draws TWO AND A HALF amps anytime it's powered. This means you need to plan on killing the battery EVERY time you shut the car off unless for "just a few minutes, do you really want to do that?

I'm pretty sure DionQ found a device that is triggered on and triggered off,............meaning the solenoid DOES NOT draw power all the time rather just a "hit" to turn it on or off............This is what I know as a "latching relay."

So far as your EFI I'm going to say "no" I think because that circuit should be key switched?