One of the proposed solutions to my EFI cranking problem is to wire a relay into the ignition system which will provide constant power to the Sniper head unit. Apparently it’s pretty common for old vehicles to have a voltage drop between the Run and Start positions in the switch, which the Sniper unit isn’t designed for. My first course of action will be to swap out the ignition switch with one of the spares and see if that makes any difference. It could be something as simple as a poorly made modern switch, which wouldn’t surprise me.
If I can get one of the two to work reliably, then problem solved. If not, the next step will be to wire in a simple relay to the ignition circuit which will provide constant power to the head unit and keep it live. There are two types I can use: a simple 30 amp on/off type like I’m using for the auxiliary fuse panel. The other is an adjustable design with a potentiometer which allows for the amount of time the circuit holds a charge. I don’t need it to stay on for 30 seconds after the switch is turned off, just enough to keep the head unit working.