328 solenoid click but starter not turning -- starter or solenoid?

I ordered a de-pin kit that seems like it has the correct keys to pop the pins out of the connectors, so I will give that a try before totally replacing/bypassing the connectors. At the very least it will let me take a closer look at the condition of the pins and their fit. These pins have two small barbs around the periphery that spring into place after the pin is pushed into the connector. A round "tube" style key should be able to slide over the pin and release the barbs if the fit is good.

 

I was only able to remove a few pins from each side of the connector, but enough to try a couple pairs to get an idea how well they were making contact. It was minimal contact, almost no friction when pushing the pins together and pulling them apart. I ended up spreading all the male pins as Lawrence suggested above, and also used Stabilant 22. We'll see how it goes. If I have any other problems with this connector in the future, I will replace it, either with individual blade connectors for each wire, or a new 15-pin connector. That will be an awkward job due to lack of slack on the engine-side harness and tight space in the wheel well to work, but should be doable (would be much easier if the engine is out). Another option is to just use butt-splices and eliminate the connector altogether, although the next guy who has to remove the engine will probably curse upon discovering that.

For reference, if anyone wants to replace the 15-pin connector, this is the modern equivalent from Molex, available on Amazon for $12:

https://amzn.to/4mTULPG

A suitable crimp tool is required to work on those pins (it curls and crimps the wings on the connector to pinch the wire and insulation).

I am not a fan of Ferrari's use of this connector or its location -- it's really awkward and asking for trouble in multiple ways. Looking back in mechanics' notes from the 1st and 2nd owners of my car (I am #3) I saw other mentions of trouble with that connector. Somewhere along the way, someone modified the bracket that holds the connector to the oil cooler duct. Upon assessing everything today, I removed the bracket altogether and replaced it with a couple cable clamps.

Tomorrow, I will take a look at the final connection at the starter solenoid and make sure that is OK. I bought a new solenoid ($35 on eBay) just in case that ends up being suspect. If I still encounter issues after all this, the solenoid is probably the last thing to suspect.

 

Well I am not sure I have learned anything after checking, cleaning, and prodding all the relevant connectors. This morning I cleaned all the connections going to the solenoid, as well as the main +12V disconnect under the car. The solenoid connections were definitely grimy but cleaned up well. While the car was still on Quickjacks, I turned the key and the engine started beautifully, so I buttoned everything up and dropped the car to the ground. Grabbed my hat to go out for a drive, but on the next attempt, no start!!

Next, I did some testing of the solenoid itself.

Across the internal coil, it measured 1.3 ohms resistance. The new spare solenoid I bought measures 1.2 ohms, so I don't think there is an internal issue with the coil on the old solenoid.

I measured voltage at the white wire feeding the solenoid #50 input. With the wire disconnected, I measure 12.5V, which is only about 0.2V lower than the key switch voltage. So that suggests the wiring and connectors from the key switch all the way to the solenoid are OK.

With the wire connected and the starter cranking (when it works!) to create load, I measure 10.2V at the solenoid #50 input. That's only 0.3V less than measured at the key switch. Again, that's a good sign I think, suggesting the wiring and connectors from the key switch all the way to the solenoid are OK even under load.

Now here's the odd one. I put a second multimeter across the solenoid input and output studs -- the two that get connected when the solenoid actuates, bridging the input +12V to the starter -- with the intention of measuring resistance to see if maybe the internal contacts were shot. To do this test, I disconnected both the input +12V line and the output line to the starter. The only wire connected to the solenoid was to the #50 input which I was monitoring with a voltmeter. When I turned the key to start, I heard the solenoid click and I measured 44 ohms across the studs, which to me suggests a very poor connection. Simultaneously, the voltmeter measuring voltage on the #50 pin read 8.8V. I repeated this test a couple times and got consistent results.

I can't for the life of me figure out why the input #50 voltage would drop to 8.8V when only the solenoid was actuated and drawing power, when earlier I saw 10.2V with both the solenoid actuated *and* the starter turning. Does this make sense to anyone? Is this a clue? Am I an idiot? Seems odd to me.

I did remove the solenoid (38 year old red loctite on the screws made it a real bear). On the bench I can manually press the plunger and get a zero ohm connection between the input and output studs, but that doesn't necessarily prove anything. I would like to swap in my new spare solenoid eventually but first I need to understand that 8.8V measurement since it could mean something important. Be glad to hear any advice! Thanks!