Ghost in the Machine?

On my '92 Roadmaster Estate which I call Buford. Here in NC it seems like we've had rain constantly daily. Still with all the weather, never had any problems until about a week ago, i go to the grocery store and upon leaving, I go to start and get a no crank condition. Lights and everything else are working OK. Good voltage on the voltmeter. Tried to jump start with still nothing. All the while during a mist of rain. Ended up having him towed home. Rain every day for the next 6 days and still no crank condition. I finally break out the GM service manual and look at the cranking circuit. Pretty much battery to ignition switch to starter with a splice between the ignition switch and starter for the ALDL test link which has a 5 amp fuse in slot #20. So my theory is to test for voltage on the fuse while key is in cranking position which if there should verify the ignition switch is good and give cause to check out the solenoid. Test light in hand, I pull the ALDL fuse, insert test light and when I go to start, the damn car fires right up. Has fired up ever since the past 3 days.

Only thing I can think of is condensation must have somehow gotten into the solenoid which is dry on the outside. All connections are good at all electrical points. No broken wires visible and the cable from the battery to the starter appears to be fine and not getting hot like some do when they get age on them.

Either Buford just said he's not moving until it stops raining or didn't like the idea of adding pontoons. Anybody have anything like this to happen?

What you describe sounds a lot like battery terminal deposits, starter on the way out, or a bad solenoid.  The rain might be a red herring and nothing more (although if it keeps raining, a carp in the air intake will also cause issues).

When Buford was misbehaving, could you hear the click of the solenoid when you turned the key to "start"?  Did the lights in the car dim when you did so?

You could take the car to Advance Auto or some other parts store chain, and they'll clamp their magic machine onto it to give you some stats on the starting/charging system.  If you luck out and get a competent employee, they might eliminate some possible causes.  If you are not so lucky, the needle on the machine will swing over to "buy unnecessary parts now".  If so, just leave and try another store and see what they tell you.

These intermittent problems are vexing.  You need to catch Buford in the act, or he'll never learn.

That's about it.

Battery terminals are clean with new battery about 6 months old. Never did hear the click on the solenoid which is why I was checking for voltage on the ALDL fuse between the ignition switch and the solenoid. Lights dimmed as they should. I've checked the charging system now that it's running and it's right at 13V where it's always been in the 8 years I've owned him. I've got a new ACDelco ignition switch, solenoid and starter in my inventory if I need it. Drove him today into town and back with no problems.

My first guess is the solenoid. Since the solenoid is part of the starter, that would implicate the whole starter mechanism. They are rather inexpensive, but a little difficult to replace. You must either remove the frame brace, or drop the exhaust to get the starter out (there may be a way to orient the starter without disassembling the above, but I have not found it.) The frame brace is one of the most miserable parts to remove, because the center bolt is designed to torture the mechanic. I put dual exhausts on my TBI cars, and the starters are now simple to replace.

Giving an update on Buford. Tested starting circuit as per the GM service manual. Solenoid not clicking so I changed the ignition switch first which had no effect. Dash lights dim when attempting to start so I'm assuming everything up to the switch is good. Next thing is to check the S terminal on the solenoid with a test light. Did that grounding out from the battery and the engine. All the wiring checks good and for giggles, I smacked the starter with a hammer about 4-5 times and he started up.

Decided to change the starter but cannot get the right frame brace off. Whoever the Ford engineer is that decided that brace needed metric bolts requiring a 18mm wrench/socket needs to be made known. Checked the solenoid connections and found the post on the S terminal was loose. (thought that was the culprit!) Got the post tightened up but just as my luck is, when I tightened the nut for the connection, the post broke. Now I've replaced the solenoid and mounted the starter which I had to adjust the shims to get it away from the flywheel. It turned over fine...once. Now it has went back to the no start condition. I'm about ready to break out my Black & Decker sawsall on those metric bolts to get that brace out as I'm convinced there is something in the starter not allowing for the ground. Maybe worn out brushes or a bad winding?

One thing to mention that may or may not be related is about 7-8 years ago, the back bearing in the alternator went out. Four different alternators including a ACDelco replacement kept causing a drain on the battery which eventually killed it. I ended up having new bearings replaced in the original to make it work. This now has me wondering if the positive cable to the starter and alternator may have somehow gotten shorted out and since they are connected on the same terminal at the battery, if there is a faulty area somewhere in the cable from it getting hot. That terminal had a very small amount of corrosion at the battery which has been cleaned along with the eyelet connectors at the other positive battery cable connector on the passenger inner fender. All of the grounds on the engine have been cleaned as well.

It would not be a short, it would be an open, or resistive connection. If it is just resistive, it will get hot when you require it to carry current. Get your VOM out, and isolate the wire before you test it. A good wire should show a direct short. A bad connection may show some resistance, and an open will show infinite resistance. Wiggling the connector may cause it to make contact and show a closed circuit.