yes the brown wire bypasses the ballast for FULL batt power at coil, full 12 volts from ign switch through Ign 2 circuit instead the reduced voltage coming from Ballast from Ign 1 in RUN.

BUT the brown wire while is connected to the ballast is ALLWAYS HOT... no matter if not being feeded from Ign 2 at ign switch. The ballast IS A SPLICE that links both circuits, just a diff voltage rates on each side due the Ballast propperties

isn't the coil wire allways hot ? full power while cranking from ign 2 or reduced voltage from Ign 1 through the ballast is allways hot. If wasn't on that way, the engine wouldn't work, that's a fact... or isn't a fact ?

If the Ign 2 wire coming from the ign switch is SPLICED INTO THE BALLAST end to feed the coil wire at full power when cranking ( bypassing the ballast )... doens't mean that THE WIRE coming from the ign switch will be ALSO hot no matter if is not cranking BECAUSE IS ON THE SAME LINE THE COIL IS BEING FEEDED AT ANY IGN SWITCH STAGE ?

so, the ign 2 circuit is ALLWAYS HOT just like THE COIL, on same voltage rates than the COIL on any of the stages. There is no way to cut the power on ign 2 circuit wire between ballast and ign switch because is spliced on the same line than the coil is being feeded!!!!! The ign switch is just selecting what voltage rate will source the coil... full while cranking, or reduced at run because that source is before the ballast.

if the Relay suggested to be used to feed 12 volts to the EFI, is able to be activated at 86 prong at the reduced voltage the coil is getting, THEN the 87 prong will be allways closed to the 30 prong AT THE REDUCED VOLTAGE TOO.

what we don't know is IF the relay actually will respond or not to the low voltage rate.

IF the relay reacts to the low voltage input at the 86 prong, THEN a diode will be required to be sure the 86 prong just will react at the bypass step coming from the ign switch on ign 2, and not react to the low voltage rate being feeded back from the ballast end.

is clear now ?

I don't know how explain it clearer if is not now

If the relay doens't respond to the low voltage rate, then won't be a problem... so we need to figure it out.

Need to note the low voltage rate coming from ballast is not a constant and changes with temperature and load going through... so teh relay COULD be responding sometimes yes and sometimes not.

conclusion... IMHO, I will add a diode on the ballast output to the ign 2 circuit ( anywhere between the ballast and the splice to feed 86 prong, BUT NOT between the splice and the 86 prong )