Cranks but won't start. Unplug ground at field spade on Alternator and it starts?

67Dart273 said
Either !!!! There is some tremendous load somewhere during crank that is causing a massive voltage drop OR there is a bad connection in the brown / bypass circuit or bad ignition switch

You should be able to run this down quickly.

With everything normalized, measure the power at the brown/ IGN2 at the key switch connector, compared to the coil. If that is good, it almost has to be the bulkhead connector. This is a simple circuit. Goes from IGN2 at the key, through the bulkhead, and to the coil side of the ballast.

If that doesn't work I simply don't know "without being there."

The brown wire inside car under dash at bulk head, in eng comp at bulk head, and at coil those voltage numbers match. I have not seen a voltage drop through that circuit at least from under dash bulk head to coil. That was the very first test I did, where I started.

I also ran jumper wire from battery to under dash brown bulk head wire. Car still would not start.