[VetteVet]

..................

Originally Posted by lsversaw

Sonoma, all new 10 ga wire, solid or stranded, should have the same conductivity. There will be far more variability in the connection between wire and connectors than there is in the wire itself. So...

My theory is that your new 10 ga wire from the battery to the terminal block initially had resistance in it due to incomplete crimps. When you soldered it (good move!) you removed the rouge resistance.

Good possibility. I always recommend jumping the solenoid at the starter. Large cable to S terminal. This removes the primary wiring to the solenoid and isolates the solenoid and the starter to just the large cable and the battery power and connections.

But my theory requires that the starter solenoid moved enough to click, but not enough to close the contacts that engage the starter, due to voltage lost through the connector/wire interface. Hmmm...

Usually the solenoid will chatter if the voltage is low. The solenoid has two coils in the electromagnet, the kick out and the hold in coils. If it holds then the contacts should be made on the starter. The starter will not turn if the large cable has too much resistance or battery voltage is low, but the solenoid will hold in. I was going to suggest a voltage drop test on the large cable for less than ten volts.

There are reasons the starter won't turn if internal malfunctions exist such as brushes or broken wires and the binding of the bendix gear to flywheel, or engine seizure. Binding is pretty obvious.
This is a good explanation of the starter function.

http://67-72chevytrucks.com/vboard/s...d.php?t=655903



Question for Those Smarter Than Me (like Vette Vet!): is it possible that the starter solenoid can click but not close the starter contacts, especially with less than full voltage?... See above

...AND is it possible/likely that Sonoma has a marginal starter solenoid that works fine with full voltage, but gets stuck halfway when voltage is low? If so, then Sonoma may have a reason to replace the starter soon, before the solenoid goes from marginal to bad.

Yes and yes