If there's voltage on one of the 87 terminals with the key off, then there's your problem. Start pulling fuses and see which one eliminates the voltage. Try to isolate the PCM wiring as much as possible and recheck all voltages at the relays. And make sure it's not something like constant voltage backfeeding from the stock harness somewhere (factory harness spliced together with the microsquirt harness). Or constant voltage on the O2 sensor heater circuit.

Is your fuel pump relay, that you pulled, black or red ?

The Mega provided diagram suggests that the relays you are to use are aftermarket. Are you trying to use the stock fuel pump relay?

The diagram shows some fuses. Have you added a fuse block for them, or are you trying to use some of the stock stuff? Some of the stock fuse holders are externally connected, which is easy to see. Some are internally connected, which is a bit harder to dope out.

I'd think that if you connected your pink wire to contact 15 of the ignition switch (connected to the battery in the run and start ignition positions), and then wired all your add on stuff just as shown, with separate relays, things should work. Happily, contact 15 has lots of wires connecting to it indirectly, and they are all red with black spiral stripes. You will find lots of these connected to various instruments, and to the alternator warning light.

The blue wire does connect to this circuit via the bulb. If you wire as suggested, and the key still doesn't do the job, you can try the pull the bulb out of the circuit and see if that does the trick, in which case the diode bit should work when added.

I put together a new fuse and relay box in the engine bay using standard automotive relays and mini blade fuses. The stock fuel pump is wired directly to the new fuse box at the rear and bypasses all the frunk wiring/relays. Stock fuel pump relay is deleted. The fact that all auxiliary things (O2 sensor, injectors, coils, etc) for the engine are operating without a fuel pump relay whilst wired according to the Microsquirt diagram has me thoroughly confused and I’ll ping the MS experts for that.

In the meantime, looks like I may need to get smart on the ignition switch wiring. That said, my voltmeter only measures power at both relays’ pin 86, as intended, when the key is switched to ON. So I think I’m wired to the ignition switch correctly, so maybe it’s my fuel pump relay pin 87 strategy. Likely more a MS wiring issue than anything Porsche-related tho.

Are you referring to the wire from the alternator D+ which goes to the GEN bulb in the dash?

What did you tap into this wire for? Did you connect anything to it?

I believe this wire only has one purpose and that is to connect the GEN light between the battery voltage and the VR. The GEN light provides current to get the alternator started and alerts the driver if something is wrong with the alternator.

Nothing else should be connected to the D+ wire.

Ah yeah, that reads weird. I just connected the alternator D+ to it directly, versus it going through the 14 pin connector.

In your new fuse panel are the fuses independent or ganged internally?
The power relay could be powering everything in the new fuse panel if they are ganged internally.

All independent (Bussmann distribution panel WITHOUT power bus). The above scan (post 19) is the backside of the panel. Fuses on left (first 2 columns of 'dots'), relays on right (5 dots per relay), bottom right is a pin number reference for the relays.

Ok, so without seeing how you arranged all the jumpers on the back of the panel I can’t guess where you managed to common all the outputs, resulting in bypassing the fuel pump relay.
At least that is where I suspect the problem lies.
Which model Bussman did you use? Most have a common power or common ground built in.

Thanks Dennis, I actually just tore the entire panel out, cleaned up the splice to pin 87 for all the fuel pump relay items, put it all together and it’s all good now. Relays are acting as expected, car turns on and off. Fuel pump relay is being triggered by the MS and she’s good to go. Wtf.

Thanks all for those that helped and for any future searchers, I’m using a Bussman 15303-4-0-4 relay/fuse panel that has NO internal bus.

Don't you just hate that? You have a problem, and try everything to figure it out. You end up taking things apart, finding nothing, putting them back together, and voila - it now works.

However, now it works, so on to the next problem.

Bizarre but in a good way. :)
Sometimes Gremlins run away when you get down and dirty with them...