Can someone help me with which wire on the ignition harness won't drop voltage while cranking? I've been searching for an answer for a few days without luck.

 

I am trying to remember from memory, but if you look under the dash, there is a run of black loom that goes to the ignition (key) and it has a couple wires in it. I think the one with constant power was white with a stripe, I forget though, just test those, and you'll find what you are looking for.

 

So far I've tested the white/red and two black/yellow's, and all three drop voltages to the high 9's to low 10's.
I'm not sure how low the voltage is allowed to drop but it's not really a consistent 12 volts during cranking.

 

Thats normal, your alternator isn't running yet, and the battery is getting drained from the starter/coils/sensors/ecu/etc and everything else trying to fire up.

 

Ok. I'll give up on stabilizing the voltage after I upgrade the ground wire and try on a bigger battery that has more cranking amps.