Technical Gotta be the Solenoid, Doesn't It?

About a month ago, I pulled in somewhere and shut the engine off. When leaving, I turned the key, nothing happened. Tried several times. No go. I got my big screwdriver out and crossed up the solenoid. The starter jogged the motor. I got in and turned the key, and it started right up. Today, I was out again, and it did the same thing, only today jogging the starter with the screwdriver didn't fix it. I had to turn the key on and start it at the solenoid with my hand on the carb's throttle. I drove it a lot in between the first and second incident with no problems. The damned thing is trying to strand me, but I'm just a little smarter than it is. So far I'm winning.
This is a 350 SBC with a stock staggered bolt starter and solenoid in my avatar Model T, and it's real easy to jump the solenoid.
So, the starter motor is good. The only things left are the ignition switch or the solenoid or the wiring. I don't think the wiring is the problem. It has been good for almost 30K miles and I don't see any smoke!! That leaves the switch or the solenoid.
I have an extra ignition switch and could change it out just to check but working under the dash ain't as easy as it used to be, or I can put it on the lift and get right to the starter though. Is there any test I can do at the solenoid to check its operation? I would like to make sure it is the solenoid before I start buying parts.

 

Not to be a wiseass but, are you sure you have a real good ground to the block? Had the same scenario with a Ford. Sometimes fire right up, other times, nothing. Mechanic where I worked came out, told me to try to crank it, he immediately saw the ground arc. Tightened it, no more problems. If that's not the problem, change the solenoid.

 

Sounds exactly like my model T except I would get a single click, then it would start normally, work normally a hundred more times then a single click.
This repeated over several months until it gave me the single click 3 times in a row before firing off.
I figured it was the solenoid vs. the battery or ignition switch, I had an extra starter laying around so I put it on and the problem hasn't returned so far.

 

Sounds like the starter brushes are sticking to the windings to me. But they said I was special in school.

 

Maybe check for voltage at the starter terminal when the key is turned to the start position? That would allow you to differentiate between starter solenoid or key switch (and/or key switch wiring).

 

Yes, I'm very confident in my grounding system. I had an ignition problem that I thought was a grounding problem, so I grounded the distributor, manifold, heads, and block all on their own ground system separate from the already established grounds.

Yeah, I don't even get a click. I wish I had a spare sitting around.

Would crossing the solenoid unstick the brushes any more than turning the key on? It will start every time by crossing it up.

 

I had a fun issue with a Chevy years ago where it would behave like that. I finally decided to troubleshoot it, I measured the voltage at the purple wire (S terminal) on the solenoid, while someone turned the key, when it was not working. And the voltage there was about 7 volts, not enough to make the solenoid pull in. I fixed it by adding a Bosh type relay to the starter circuit, so that the ignition switch only had to power the little relay, and the relay powered the solenoid.

But there could be other things going on with your car. As mentioned, if the brushes aren't making good contact, then it won't make any noise when you try to start it, but disturbing the starter (ie. hitting it with a rock) can make it start working.

Good luck, it's frustrating...

 

Sounds to me like it's the solenoid. If memory serves, this is the starter that would do that when the copper disc and the contacts in the cap in the solenoid got worn out (burned). We used to take the disc out and turn it over so it contacts the unused side of the disc. Turn the contacts 180 degrees so you get a new contact surface. Problem solved and would usually last many years. Take the end off the solenoid to check it. These Delco solenoids are one item that's repairable although I do like the idea of hitting it with a rock.

 

It could. I have worked on ot cars where you could turn the key all day long and the starter wouldn't turn but jump the solenoid or tap the starter and it would start.
How close is the starter to the exhaust?

 

just go buy a new one

 

A bad ground would prevent him from being able to "jump" it at the solenoid, which he is able to do.

 

Thanks. That's a good test. Key turned to start and there should be 12 volts at the S terminal. And it is a purple wire in my harness.
I've used the hit it with a hammer method before but I don't think that is applicable this time.
I hate electrical work. I wire my own cars with kits so all you got to do is land the wire where it says right on the wire. The worst thing about electrical is trying to fix intermittent problems. Well, I guess I am lucky? this problem at least has moved past the intermittent stage.

 

Hell, I'll give a couple raps a try. Can't hurt anything.
It has lake pipes. No where near the starter.

 

Yeah that's probably where this is headed right after I do Squirrel's test for 12 volts at the S terminal

 

If are crossing the small S terminal to the battery terminal and it starts there nothing wrong with the solenoid. If jumping the battery term to the lead that goes into the starter it would run not engage the flywheel. You need to look at the wire and switch going to the S terminal jumping it with a screwdriver is taking that out of the system.

 

Sounds like "heat soak" [what squirrel described]
A jumper from the battery to the "S" post usually gets you going./

Then look at the Ford starter relay solution for Chevy starter motors. [this requires bridging the "S" post]



This is how squirrel suggested [it doesn't require bridging the "S" post] and gives a full 12v and 30-40a max to the solenoid.
Post #'s 30 and 87 need wires that can handle a decent load [and be as short as practical]

 

Thanks for showing both relay options, Kerry

 

Where's the fun/ challenge in that ?

 

A relay to switch a relay ( and on and on) always seems kinda redundant , more places for problems & silly to me ( unless you have inadequate wiring or an undersize switch ?

 

Or put a new solenoid on it. Lippy

 

Hahaha! The Mobius Strip of "Auto Electrics"

I always thought that also...... But the problem is most OEM ignition switches only pass 5a in the cranking position [add losses from heat soak in the wires and the solenoid]
This has been a Chevy "battle" since tube headers were first used.

If you had a simple push button starter that can handle 30a and wires to support it ,then this would be a moot point.

We Always used Ford starter solenoids on race cars [for safety as well] to circumvent heat soak.
Denso starters don't have this issue

 

If you have block hugger type headers, they cook solenoids.

 

I agree with Kerry.
If you can get it to turn over by bridging a screwdriver or such across the the main supply to the S terminal its an inadequate voltage supply problem from your switching source.
My old F100 (351C) would have trouble starting after 12+ hours on the road from heat soak, a simple Bosch relay as described above fixed it immediately.

 

Just go with one of these as a secondary circuit and use only as needed https://www.amazon.com/Dorman-85984...hvlocphy=&hvtargid=pla-4584207577565562&psc=1

 

Most heavy trucks are set up with a "mag" switch which is controlled by the key switch. It then powers the solenoid terminal on the starter solenoid.

 

I have used Ford solenoids for decades, I always carry a spare in the trunk. I made up a few copper jumpers a couple years back, time to get a bunch of these either photo-etched or water jetted.

 

Yes, that makes sense. I did late last night change out the ignition switch for a known good switch. No change. Still complete silence when the key is turned. So, it is not the switch.
I wired this car with a kit almost 10 years ago. As Squirrel said a purple wire is landed on the S terminal of the solenoid. All the wires are wrapped from the starter to the firewall and I lose track of it. I don't know where it goes a after that. I have been standing on my head under the dash for an hour trying to find that purple wire. No luck. Where would it be terminated?
I feel like such a dumb ass. I built the damn thing and can't remember what the hell I did.
I think I still have the instructions for the wiring kit in my file. I'll have to dig it out.

Whoa! Wait a minute. A new thought. Could the neutral safety switch cause this???

 

I don't believe that heat soak is the problem. It has lake style headers. The tubes come straight out from the head about 8". The starter couldn't be any farther from the header. I wouldn't think that a heat soak problem would wait almost 30K miles before rearing its head.

I hope the problem doesn't take Ford solenoids or relays to fix, but I appreciate the info and will file it away in case I need it. I am a firm believer in the K.I.S.S. method.
Thanks

 

The neutral safety switch can easily contribute to the voltage drop on the purple wire.

 

Yes on the neutral safety switch, and the purple wire should be on the back of your ignition switch. But if you can use the old east side screwdriver trick on the solenoid and start the car, I'd go get a new starter. At least a solenoid