Hot Rods Gm solenoid starting problem

this is a long story so sit back. 1966 Chevrolet. When I try to start the car no click and no start. Starter does not move or make a sound. After three to four times turning the key it will start. New ignition switch new wiring new starter an solenoid could be 10 years old but not used that much. red wire leading to back of ignition switch 12v. Purple wire from back of switch 12v when in start position. Purple wire at bulkhead connector 12v when key is in start position. Purple wire to S terminal when not connected to solenoid 12v when key is in start position. When purple is connected to solenoid and key is in start position 7v and of course no start. After 5 or 6 tries purple wire at 12v and starts. please help.

 

You have a corroded wire between the bulkhead connector and the S terminal(providing your 12v reading at the bulkhead was with the wire hooked to the S terminal).

 

All new wiring.

 

Is the gauge of the purple wire adequate? I've made that mistake, but it lasted for quite a while before it started failing. I hate intermittent faults!

Chris

 

Possibly a bad connection. Allowing good voltage without a load being applied. Once the amp load is applied the circuit breaks down.

 

did you use dielectric grease on the terminals? a few years ago, all of the aftermarket solenoids were **** and only lasted a few months. I carried a screwdriver to jump start my 39 Ford and used it so much that the end burned away. try a different solenoid

 

Dielectric grease is an insulator.
Use and anti-oxidant compound such as Ox-Guard to promote conductivity while protecting the connection.

 

If you have 12v at one end of the wire and 7v at the other the only explanation is a bad wire.

 

All original wiring

 

A good test to isolate the problem is a remote starter switch. They come with two clips and you can hook one to the battery post and one to the S terminal. Then push the switch and see if it tries to crank. If it does the issue isn't in the starter, it's in the switch, or wiring from the switch.

 

Is there a neutral safety switch in the starter circuit?

 

7V when ignition is in start position with no start, !2v when it does start.

 

No, wires from NSS were connected together byp***ing the switch, 4speed no NSS.

 

The biggest fallacy when dealing with anything that you are having trouble with is that it is "all new or all original" so that can't be the problem.
The issue isn't in the purple wire, the issue is in what ever has a resistance that eats up 5 volts when you go to crank the engine.
I fought hot start issues with my 77 1 ton dualie with the 454 in it from the time I bought it until I figured it out.
That included new battery, doing the Ford Solenoid fix thing. Replacing the starter at the gas pump at the Safeway store gas station in North Bend Washington while towing my sailboat.
The fix? taking those damned 4 gauge battery cables off and putting 1 gauge on. The 4 gauge wire couldn't carry the load to over come the extra drag when the engine was hot.
At the gas station a Kid with a little pickup pulled me about two feet so the tires would be turning when I dropped the clutch and clutch started the truck. If it would roll it would start.

Still you issue is an excess resistance somewhere in the start system.



Posibilities.
1. A connection in the wire from the S post on the switch to the S post on the starter will not carry the amps needed to kick the solenoid in. Or the wire of choice is too small to carry the load.
2. You have a piss poor connection in one of the battery cable connections. That is usually where the battery ground cable connects to the block or engine component. The problem more often than not is too ******** much paint in the spot you didn't s****e to clean bare shiny metal to get a good connection. Yes I am that guy who has made a couple of guys with fresh builds cry when I took out my knife and s****ed the paint away after I unbolted their ground cable so the cable would actually ground. Same thing, enough connection to show 12 Volts with key on but not enough connection to to carry the amp load of the solenoid or starter.
3. Battery new or not just flat doesn't have the poop to crank the engine. I've replaced new battries that I had installed in a shop because they just flat didn't have the poop to handle the load even though they showed full voltage. Put the load tester on them and they ****ped out real quick.
4. Starter locked up because that one time it did try to turn the Bendix got stuck in the ring gear and now it won't spin because it is locked up.
5. Starter or solenoid is NFG even though it is allegedly new or in good shape.

If you jump the solenoid with a screwdriver or remote starter ****on what happens? That would be my first test and go from there.

 

Sounds an awful lot like an issue I had with my 86 cutl*** as a teenager. Ended up being a bad solenoid. There's a disc inside that rotates and makes contact. In my case there were a few thin spots. So click click vroom was how it tended to go

 

Solenoid ?
On a 63 Chevy II I worked on , the wire harness block half's had bad connections p***ing through the firewall

 

If the click click is what you heard, I don't hear anything until it decides to start.

 

12v coming out the bulkhead connector on the purple wire connector.

 

10 year old solenoid, you have it right there. It could be a green connection at a terminal too. My car, I would pitch the solenoid and get a new quality one. I byp*** mine and run a Ford type solenoid on the firewall.

 

This is a very real possibility. I spent months chasing this problem on my car. A larger purple wire fixed mine.

 

If I’m not mistaken, the purple wire is only byp*** for the ignition. Should not have anything to do with start. Don’t even need it to crank. Also, 12v means basically nothing. Will that wire light a seal beam headlight? In other words, can it carry the load to make the solenoid work? I’d jump the starter like others have suggested. Go from there.

 

The purple wire is the GM coloring for the crank wire. Not sure about the ballast wire coloring though.

Chris

 

You just performed a voltage drop test. The results tell you that the problem is up stream from your connection point. That means your problem is between the bulkhead connector and the ignition switch. The next thing I would do is the same test right at the ignition switch (with all wiring connected). My guess is that you will see the same 7 volts pointing to a problem in the ignition switch itself or the power feed to the ignition switch. You have to keep moving your voltmeter positive probe closer and closer to the battery (in the circuit) until you find a spot where the voltage stays at 12 volts. The problem then lies between the last point you saw 7 volts and the spot where you measured 12 volts.

 

12v coming into horn relay 12 going into volrage reg coming out to in bulk head connector. 12 to back of ignition switch. This is with battery hooked-up. at 12.8v. Purple wire at back of ignition switch with key turned on to start position 12v. Purple bulkhead connector 12v when key is on in start position. Plugging in the engine harness into bulk head connector wirhout connecting purple wire to S terminal wit key on in start position 12v. Now connecting purple wire to S terminal with key on in start position 7v. Until I keep turning key to start position a number of times 12v and starts. And it seems if I turn car off and try to start again right away it will start.

 

You need to do your testing with the purple wire connected. With the purple wire disconnected, you are doing an open circuit test. Open circuit testing just tells you that you have a continuous circuit, it doesn't tell you what happens when you load the circuit. With the purple wire connected, check to see what voltage you have at the ignition switch. That will tell you where the voltage drop is ocurring. Your symptoms tend to point to bad contacts in the ignition switch since turning it multiple times makes it work. Testing the voltage at the switch will confirm that the switch is either good or bad. 12 volts at the ignition switch in the start position means the switch is good, 7 volts points to the switch or the power feed for the switch. It's a quick, easy test.

 

Now just how in the hell do you figure that? If it were an insulator a light bulb wouldn't work after you coated it and put it back in, nor would a plug in connection still work after you greased the connectors. I put dielectric grease on all my connections, battery included and everything still works fine.

 

I gave both examples purple wire on new wiring harness not connected to the S terminal key in the start position 12v. Purple wire connected to the S terminal with key in the start position 7v after 5 to 6 times turning it on and off 12v car starts.

 

Just change the friggin starter. Move on .
OR
There have been tomes written about electrical testing. Automotive & otherwise , tip to the library or look on line ....YAWN !!

 

There's another way to test this that will pinpoint the fault. Do a 'difference of potential' test. Rather than reading to ground, read voltage between the accessible points in the purple wire. With both ends connected and the ignition switch turned to 'start', start reading between the various points with the meter set to 12 volts; switch input to start terminal, start terminal to inside bulkhead connector, inside to outside bulkhead connection, outside to solenoid, solenoid to ground. You know the last one is 7V. If the various connections are good, the meter should read under .5V (I would expect to see less than that) between any given two points, that's the actual drop between those points. See a big number at any one measurement point, there's your bad connection. If the problem is between the switch and the solenoid, the drops should add up to the total drop, about 5 volts. If that's not what you find, the problem is the solenoid coil. A partially broken wire or poor solder connection probably...

 

But have you checked the voltage right at the ignition switch like I suggested? Just where are you checking that you see 7 volts. Where is the voltmeter connected? Or, are you looking at a dash mounted voltmeter? That would change everything.