VP, path from battery + to ign coil + (looking for bad connection)

[Circlotron]

I'm tracking down an ignition problem. When the engine is cranking there's about 11 volts at the battery but only about 6 volts at the coil + terminal. This would explain why it is hard to start on gas when it has been sitting overnight. A cyl fires here, a cyl fires there, then another, then finally it roars into life.

So... what I want to know is, what is the path from the battery to the ignition coil? How many relays and fuses and switches and plug and socket connectors does it go through to get from one end to the other, and in particular, where are they all located? I'm thinking it a a corrosion or oxidisation problem or bad relay or suchlike. Is it common on these cars?

[Circlotron]

Looking at a wiring diagram for October '89 onward VN at least, the power for both injectors and coil come from the EFI relay.
Do these give much trouble?