Arrived home and turned off truck, pulled key and the engines still running. Accessories and gauges all turn off. Replaced the ignition lock cylinder and for a few weeks it was fine. Last week had the same problem with the new ignition. Any help would be greatly appreciated.

 

Any history? Did it always do this? Did it just start?

Did you do any wiring shortly before it started that could explain it?

Does the ignition module and/or coil still have ~9-12V to it once you turn the key off? If so, you've got a wiring issue and it's not correctly wired to the run/start positions on the ignition switch. If not, it sounds like it's "dieseling" which could mean you've got some significant hot spots/deposits in the engine.

 

Stuck solenoid? Smack it with something soft like a shoe.

 

The Ignition lock cylinder I'm sure was original to the truck based on the condition of the key. Since I've had the truck, I've replaced the ignition module, alt, cap, rotor, plugs, plug wires, rebuilt carb and a few other things I can't remember off the top of my head. As for this problem, I've been driving it 60-80 miles a week for about 2 months, replaced the lock cylinder, 3 weeks trouble free driving, then same problem. The new lock cylinder was bought at advance auto, and while it may be defective, I find it strange that it was fine for about 3 weeks before I experienced the same issue. It's not dieseling, the engines actually running. I can put it in drive and go (no accessories etc.. because the keys off/out. I know I can replace the recepticle for the ignition lock cylinder, but before I buy/experiment, I thought I'd try and get some input here.

 

ignition module and/or coil still have ~9-12V to it once you turn the key off?

Haven't tried this yet. I'm at work now, but will try when I get home.

 

Yes its called the "ignition switch", it has the tumblers/lock cylinder (the thing the key goes in) inside it. I know YOU know that but I am explaining it for others.

It is held in the dash by a 3 notched threaded on ring on the outside of the dash. Tap at an angle on one of the notches with a flat tip/hammer and get it to loosen up. Then thread if off and replace the ignition switch assembly.

 

Just for clarification, the lock cylinder will have no effect on whether your truck runs or starts or anything unless it is physically broken. Now, removing and replacing the cylinder put the internals of the ignition switch in a state it normally is not in. Which could be why it fixed it for a few weeks. The inside of your ignition switch looks something like this:


When you removed and replaced the ignition cylinder, you most likely cleaned a small contact surface or moved something back in place. I would say the internals are either dirty, or broken. Either case it needs replaced.

 

don't presume I know anything and thank you for the clarification !

I will order/replace the "switch"

Thank you everyone for the input

 

I put a new ignition switch (and solenoid)in mine yesterday and shortly after the truck continued running after the key was off and out. . I didn't notice gauges or accessories but I got out and pulled the back small wire(closest to cab) off the solenoid and it shut off. Idk what happened either.. I asked this in a separate thread about my elec problems.

And in the past 8 years I've owned it. Twice before and once yesterday the truck continued trying to start without the key in the "start" position. Yesterday was my first new switch but the second solenoid or third.

 

Stayed running or stayed trying to start like a stuck starter solenoid?

 

Some of both. Years ago the starter stayed on and I had to jump out and unhook the batt..and also yesterday morning while the wires were unhooked we were testing voltage and had it on the little wire(which would of tried to start it if hooked) at the solenoid.
And then new problem yesterday afternoon with the new switch installed the engine stayed running with the key out and off

 

I replaced the solenoid a couple of weeks ago because the old one would not start the engine . Then just today after starting good everyday since then , it would not shut off . So with key in my pocket i tapped on the solenoid lightly with a small hammer and it shut off . Well not wanting to do that often i took it in for another exchange and got another probably cheap made solenoid . I put it in my tool box as a spare and installed a used "Motorcraft" brand one. So tap on the solenoid that may be your problem part.

 

I unhooked the small wire( which I do not know what does, its not the fire from the key_the one beside it) and my engine shut off. Brand new solenoid. . kept the old one for a spair though.

 

So, 12-14 volts at the coil then. I'm guessing the wire you pulled is on the I terminal of the starter relay/solenoid?

It's used for send full voltage to the coil for easier starts when cold or during high amp draws (starter motor). Leaving this on might cook a coil if it's not designed for full voltage. Usually coil power goes through a resister wire located in the cab wiring harness from near the fuse panel to around the heater panel. I hate this wire, as it nearly burnt my truck down... but that was my fault

Edit: Also try and use this type of starter relay, I've had way too many problems with the older original barrel types:

 

Dad said he thought it was for extra coil voltage if he had to guess. But we didn't know for sure. That is the one I pulled off the relay to turn the engine off.