I have the exact same problem with my 68 GMC.  Every now and then,  like over the last 6 years,  i would get the same problem.  Totally random and at the worst possible time.  I carried a screwdriver to jump the starter under the hood.  Worked everytime

I narrowed it down and checked everything same as you have done.

Thought it was a neutral safety issue for sure,  exact symptoms, but not, Traced the purple wire,  bulkhead,  everything you have done

I thought for sure it was the ignition switch, so i changed that a few years ago.  but then got the problem at the most inconvienent time.

That had me totally stumped.

This spring it happened again a few times.

Now i have a bad habit of never fully tightening my battery terminals.

That was it,  as long as they are clean and tight,  i have never had the problem again.  Thats what i would do.  I bet it works

I have good heavy cables, clean,  good solenoid, frame and firewall groundstraps,  the whole 9 yards,  but for some reason, this old truck likes really tight battery connections!

Crazy, but true!

-- Edited by beaumontguru on Monday 4th of June 2012 10:33:04 PM

I should add, it's a manual trans, there are no safety switches. The wire leaves the ignition switch, goes through the bulkhead connector in the firewall and right to the S terminal on the solenoid.

Well, crazy as it seems, maybe that's all it is. Why else would it work fine the second I hooked up the charger....

I have brand new cables on it with the engine swap but you are right, I always unhook one when I park the car.

Hmmmmm.....

I am going to clean and tighten the cable tomorrow and try it.

I just can't figure it out though. Full voltage until the wire is connected to the solenoid. Just plain stupid.

You know what, I think next time it does it I am going to try boosting it. If it goes right away, that pretty much tells the story.

I have seen the nuts that hold the terminals on the solenoid  bakealite cap"loose" causing this problem. Under the bakealite cap are contacts ,these could be crappy. Remember,they don't make stuff like they used to.   John

I had the same problem with my 65, but usually only when hot, so did the remote solenoid trick, no more problem. Funny thing is when I switched the 283 out of the 65 and into the 59 the problem followed it. So in my case obviously a starter/solenoid issue although we tried every thing in the 65 to get it to work, We changed starters, solenoids, cut the spring down, nothing helped. Gave up, figured a bad wire somewhere, and just did the old "hot start" kit. Did that again on the 59. Some day I'll fix it right.

68 427 wrote:

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I HAD A PROBLEM LIKE THAT IN MY '66 BISCAYNE. I'M NOT SURE IF IT WAS THE PLUG , OR THE IGNITION SWITCH, BUT I WOULD WIGGLE THE PLUG GOING INTO THE SWITCH AND IT WOULD FIRE UP. I TRIED CLEANING UP THE CONNECTION, BUT IT WOULD STILL DO IT. IT WOULD ONLY HAPPEN ON THE RARE OCCASION SO I NEVER WORRIED TOO MUCH ABOUT IT TO FIND THE REAL CAUSE (PLUG OR SWITCH).

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 I tried wiggling on "crank" with no luck but I'm planning to remove the connector and possibly even run a new wire from there to the solenoid for testing.

seventy2plus2 wrote:

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On the solenoid terminals, remove the top nuts and wires, and ensure the terminals are tight from the factory.   It wouldn't be the first time the terminals weren't tightened.

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 Yes, I learned that one the hard way many years ago. NEVER trust a new part! And then to top it off I overtightened them and broke the new solenoid...

I have exhausted all what I see as the "common" stuff that I've encountered or read/heard about over the years.

I spoke with 67 Poncho late last night and he gave me a couple of new ideas. Till now I have been working from the ignition to the starter but now I'm going to go back to the battery and start there.

The starter receives 12 volts from the battery through the starter relay. When the key switch is turned to "START," voltage flows from the battery to the starter relay. The starter relay directs battery voltage from the battery to the starter solenoid. While the starter is activated, the starter bendix engages the flywheel, cranking the engine over.

Chances are that if a starter solenoid is bad, the starter will not work well enough to start the engine.

I vote for solenoid

Well,   you're not gonna believe it.  Got out of home depot and the truck did it to me again.  first time in a couple years.  Get out,  jump solenoid with screwdriver,  good to go.

Then i remembered that 2 nights ago i changed my alternator and had to disconect the battery,  sure enough,  there in the home depot parkinglot,  i was able to wiggle the battery connection at the battery.  Even wiggling it, does not help,  so when i got home,  tightened them up really good,   problem solved

Every time it happens is when its hot out too,  or long driving.  Probalby just enough extra stress on the system,

I know,  its crazy!!!

beaumontguru wrote:

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Well,   you're not gonna believe it.  Got out of home depot and the truck did it to me again.  first time in a couple years.  Get out,  jump solenoid with screwdriver,  good to go.

Then i remembered that 2 nights ago i changed my alternator and had to disconect the battery,  sure enough,  there in the home depot parkinglot,  i was able to wiggle the battery connection at the battery.  Even wiggling it, does not help,  so when i got home,  tightened them up really good,   problem solved

Every time it happens is when its hot out too,  or long driving.  Probalby just enough extra stress on the system,

I know,  its crazy!!!

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I have the exact same problem with my Beaumont seems worse when on a hot day or after a long drive in the hot weather. I put a heat shield on the starter ,but this did not help. Also put in a relay that may have helped a little, but it still does it every once in awhile. It is frustrating!

What year and engine in the truck?