Truck wont shut off

[rwilly]

Another hurdle on my 68.
When I turn off the key, the truck keeps running.
I have tried-
New Coil.
New ignition switch.
New key cylinder.
New Solenoid.

As far as I can tell the wires at both ends are hooked up correctly. On the solenoid end, the Starter wire and the Ignition wire are correct, if I reverse them, the starter will stay engaged.
The switch end looks like it should.
As it is now, I pull the coil wire to shut it off, but that is getting annoying.
Tell me if you can see anything out of place in these pics.

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[rwilly]

I am following the wires, studying the diagrams, wracking my brain, boiling my peanut, and this is one big rats nest! The PO did an alright job hooking up all the wires when he did whatever he did, but you would think that not being able to shut off the engine would be something he would've looked into.

I am sure you all know what I am talking about.

Weird thing is 2 of the wires pulsate, flash like a turn signal when the key is turned on. They are ignition wires.
All a process of elimination I spose.
If you hear a loud banging noise, it just me hitting my head upon the wall over and over again!

[sargentrs]

The first place I would start is at the solenoid. These are notorious for being bad right out of the box. Looks like you have some stray wires in that area. Check the "I" terminal for voltage with key on, then with key off, then the wire itself in the same scenario. That's what kills your engine when you turn the key off. If the wire voltage is hot with key on and dead with key off, then I suspect a sticky solenoid issue.

[Mach428]

I believe the terminal on the right side of the solenoid provides power to the coil when the key is in the start position only. The ignition switch is what turns the motor off by de-energizing power to the positive terminal of the coil when turned. off.

[rwilly]

Thanks guys.

I tested the wire and its got power when the key is in either position. I am thinking it has to do with the pink wire from the iggy switch. Hopefully I can get around to it this weekend.

[69Ford]

Try pulling the brown wire off the starter solenoid and see if everything works. All the brown wire does is bypass the resister wire to the coil when the solenoid is engaged to send a full 12 volts to the coil for better starting. When the starter solenoid disengages it defaults back to the resister wire which lowers the voltage to about 9 volts this is to prevent the points burning up. Check to see if there is continuity between the battery side off the solenoid and the brown wire side with the key in the off position. If there is you have a bad solenoid. In your picture the brown wire is the right one. Is this a points truck.

[rwilly]

Yes, It's a points truck.
When the key is on, there is around 6.5 volts between the "S" and "I" terminals. When the key is off, there is no voltage. I can pull of the terminals and the truck keeps running. All the wires appear to be hooked up correctly except the pink wire off the switch itself. It is plugged into the same terminal as the red w/green stripe.

Checked for power between battery cable of solenoid and brown wire and I got 12V when off, and 6V when key is on.
That doesn't make any sense.

[69Ford]

Ok I looked a the wiring diagram and it shows the brown wire off solenoid going directly to the positive on the coil. The pink resister wire off the ignition switch also go's to the coil connecting to the brown before the coil in a connection. So I would check the ignition switch by pulling the brown wire off the solenoid. Then at the hot side of the coil with the wire disconnected check for power at the wire in all positions of the ignition switch. You should only have power when the switch is in the RUN position it should be between 6 and 9 volts. If you have power in any other position ACC, OFF, START, the switch is bad or someone has wired in a alternative source at some time in the trucks life, slight chance that a source has shorted to it but I think its very unlikely. Next check for power on the solenoid pull the brown wire off and check for power at this terminal on the solenoid making sure the ignition switch is in off position. If there is power there with the solenoid disengaged the solenoid is bad. Now I do not know the year of your truck but I went off the 69 diagram. Here's a link http://www.fordification.com/tech/wirin ... rging2.jpg

[69Ford]

Checked for power between battery cable of solenoid and brown wire and I got 12V when off, and 6V when key is on.
That doesn't make any sense.[/quote] Getting 6 volts when the key is in the RUN position makes sense because the resister wire is tied in with the brown wire. should be 12 volts in the key START position. 0 volts in the key OFF position. If I'm understanding correct you are getting 12 volts in the key OFF position at the brown wire. Should not have voltage this way. It is sending that voltage to the coil keeping your truck running. How are you shutting the truck off. Power to the coil with the truck off will fry the coil. Here's my diagram hope this helps

My Diagram.jpg

[rwilly]

I turn the truck off by pulling the coil wire off the dist.
I tried 2 solenoids.

I hope the pics are clear enough. I tested 2 solenoids. In these pics, the key is off. I have the positive lead attached to the positive cable of solenoid, the negative lead is plugged into the brown wire.

There must be a reason the coil is not getting fried. I tested the coil between + and - when the truck is off and there is no voltage. Good thing!
When I bought the truck the white solenoid was laying on the floor, so I am guessing the PO had troubles with it also. He was kind of a strange dude. He just let the truck sit in the field, rotting away.

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Edit- I decided to focus on the switch itself. I pulled the red w/green stripe wire out of the socket it was sharing with the pink wire. Now the truck shuts off. Tomorrow I will see if the proper voltage is being maintained at the solenoid. Hopefully this cures it, but I have feeling the voltage will not be reduced to the coil.

It's my bedtime, it's too hot (90deg), and I am fighting a flu virus of some kind.
Thank you for your advice!

[69Ford]

If you decide to go with electronic ignition you will want 12 volts to coil at all times Pertronixs makes an ignition that installs just as quick as points about $100. Here's a reworked wiring diagram from the site.

wiring-1969charging2.jpg

[rwilly]

Conclusion--
By messing around with the wires at the switch I was able to get it to shut off with the key, but then it was charging. Or I was able to get it to charge but not turn off.
I ended up taking the red w/green stripe wire and hooking it up to the fuse block to a terminal that is hot only when the key is on, the pink wire goes to the spot on the switch the red w/green stripe wire is supposed to go. Now it charges at roughly 14V, and shuts off when I turn the key off. The voltage at the brown wire when running is a little bit lower at around 3 volts, and there is still 12 volts at the brown wire when shut off.
I tried to chase the wires down and straighten things out but I am thinking the PO was a tweaker. Some of the things done make no sense.

What's funny is, in a few months when I am having troubles, I will find the wire that I hooked to the fuse block and I will cuss out the PO!

[69Ford]

I'm glad you got it working.

[sargentrs]

Thanks for posting your fix!

[tqwrench]

This happened to me today after I got back from buying parts for another car I was working on.

I drove it about 15 miles round-trip with the a/c on high or medium the whole way and when I got back, I turned the key off and the truck kept running. I messed around under the dash and got to the ignition switch connector, found it warm and when I wiggled it, the truck stalled. I immediately disconnected the battery and later pulled the connector off and the switch out.

My truck is mostly original, so it had the original switch and wiring. I found the thick yellow wire melted to another wire right behind the connector (pink/brown?).

Looks like it's time to replace both. That's what brought me here. I need to find the connector part number. My research shows this happened quite a bit to anyone with the bullet terminal style switch.