Would turn truck off and it keeps running. Replaced ignition cylinder: same thing. Only intermittently. Thinking ignition wire but how do I test it to make sure? Any help is appreciated!

 

Welcome to the forum

Most likely ignition switch, the part under the steering column above brake pedal
The key switch rotates and moves a rod inside the column and that rod slides the ignition switch into its 4 positions, ACC, OFF, RUN, START
Simple diagram here: https://encrypted-tbn0.gstatic.com/i...vTKrg&usqp=CAU
The older switch cases would split, and could be repair with wire tie/zap straps

Ignition switch looks like this: https://i.ebayimg.com/images/g/fKkAA...e/s-l1200.webp

 

THank you RonD!! I will check that out today and let you know!

 

Replaced ignition switch. No go. same thing with not turning off. Is the actuator that slides on the switch adjustable?

 

No adjustment on actuator rod

While ignition switch was out did you try turning the key back and forth to make sure actuator rod was working like it should?

And with ignition switch still detached and battery hooked back up, could you start engine, then shut it off manually moving the ignition switch?

 

Yes. I made sure rod moved back and forth. Truck won't start without switch hooked up to actuator rod.

 

RonD I removed the ignition wiring from the switch and truck stays running in key off position. Do you know where the ignition relay is so I can check that?

 

1984 has no "ignition relay"
With key on the ignition switch sends 12volts out to spark system on the red/light green stripe wire
With key off 12volts is cut on the red/green wire, so no spark and engine dies

Fuel is a carburetor using mechanical pump so doesn't need 12volts


The red/blue stripe wire from ignition switch activates the starter motor with key turned to START, so doesn't power spark system

 

I figured this out by accident and thought I would share so someone else out there isn't pulling their hair out! Truck turned over once then nothing. Checked switch at clutch pedal and pushed the rod in and out. Now it starts AND shuts off.....