The white wire coming through the firewall looks like it was supposed to connect to the condenser, but the end of it is just hanging down by the distributor/condenser. I can't see anything else it would have connected to. Plus it looks like an original wire vs some of the other cobbled stuff he has in there. My aim is to get the wiring back to its original configuration.

Currently there is a green wire that runs directly from the (-) term on the coil to the condenser/points. That, I'm almost certain, is NOT RIGHT. It's not on the diagram.

There is also a red wire connected to the same (-) term on the coil that runs through the firewall. I believe that is proper, and it should be running toward the tach, creating the first leg as the "sensing loop".

From what I see on the diagram, both the red wire from the (-) coil lug and the white wire from the condenser/points should both run to the tach to form a complete circuit through something in the tach - it's a symbol that looks like some sort of reluctance coil maybe?? (I'm not an electronics expert, obviously) That must provide the "sensing" source you mentioned.

The (+) lug on the coil has two brown wires connected which is correct per the diagram - one brown wire brings power from the fuse block to the (+) on the coil and the other brown wire connects the (+) on the coil to the FI relay. My assumption is that these two brown wires have NOT been tampered with.

According to the diagram, there should only be three wires connected to the coil: Two browns on the (+) terminal and one red wire on the (-) terminal.

So I'm wondering if the "sensing loop" which consists of the red wire from the (-) coil to the tach - through the reluctance coil/ring - and then back to the condenser via the white wire, provides a certain level of resistance that lessens the wear and tear on the condenser and points. And that by running a green wire straight from (-) coil to the condenser, has caused the condenser to fail prematurely. If the condenser did fail, then it only lasted about one hour of running time. I have not yet tried disconnecting the red wire from the coil and checking for continuity/resistance through the complete "loop". I could also check for continuity between either the red or white wire and the chassis to make sure there is no accidental grounding going on.

The tach is not reading correctly. The needle jumps wildly in a hit/miss fashion, making me think the red wire from the coil is trying to energize the loop and it is occasionally finding a ground path that causes the needle to jump.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (currently leaking brake fluid all over the garage floor)