Nice car! Once it starts with the jumper, does it keep running with the jumper taken off? Sounds like you have a bad connection somewhere in your ignition hot wire. Should be black/pink on a 69, When the circuit gets damp it causes enough resistance that the current flow stops. May want to take the wire off the coil and check the terminal connection, could be that you have to crimp on a new one. Also check the wire all the way back through the circuit for splices that may be loose or corroded. Or it could be moisture in the ignition switch.
-"Once it starts with the jumper, does it keep running with the jumper taken off?" - yes I remove it immediately and it will start the next day and the next The problem only exists after sitting a week or more in damp weather summer or winter
-" Should be black/pink on a 69, When the circuit gets damp it causes enough resistance that the current flow stops." where is this black/pink wire ? Is that the one on the coil?
-"May want to take the wire off the coil and check the terminal connection, could be that you have to crimp on a new one." I did this a few months ago
-"Or it could be moisture in the ignition switch." Is this the switch on the steering column? I replaced that a few years ago but perhaps it went bad
I have the shop manual and will trace the coil wire back
Have you tried immediately hooking up the coil wire after a week to see if it makes any difference. Could be an intermittent issue in your ignition switch where voltage is not being applied during cranking or it is very week. I would also check the voltage at the coil during the crank cycle and run to confirm. If I recall, 69 is the oddity wrt applying coil voltage during crank. In 67/68, voltage during crank also comes up from the starter solenoid.
Sorry, I gave you false info, the wire to the coil in a 69 is supposed to be Black - Purple not Black - Pink. It starts as black /pink at the switch and changes to black/purple at the firewall junction block.
Good Idea about the wire piercing circuit tester, next time it doesn't start you could check that wire all the way back to the switch. May have to disconnect the starter and have someone hold the key to start to keep the circuit in start mode rather than run mode if the switch has two individual circuits, one resisted and one full volts, a start and a run, leading to the same wire.
Yes the start power to the coil in a 67 and 68 comes from the starter solenoid, and when the key is in run the power to the coil is from the key through a resistance wire. The 69 only has the power wire from the key. I'm not sure if the ignition switch has an internal resistor for the coil in run mode and no resistor for start mode or if the coil can take full voltage in both. I believe it was about that time non-resistance coils were being used but who knows.
