I swear sometimes I think my truck has trouble that noone else has. But then again, I am sure one of you have gone through this. I have a 69 with the a stock 390/360 ignition system. It used to be that every once in a while after I turned the key to start the engine the ignition system would shut off as soon as I took the key out of the "start" position to the "on/run" position (NOT the entire electrical system would shut off- lights and radio still worked) Now the truck does it all the time and I can't even get it started. Before I had to tow it home, while driving the ignition system would shut off but all other electrical would still work. I can tell that the engine is running while I am turning the key because I can here the starter spinning really fast and I can even rev the engine with gas peddle, but as soon as I release the key to the "on/run" position the engine stops. I am certain that this is an electrical problem.
These parts are new or check out OK: Distributer, cap, condensor, points, plugs, plug wires, coil, alternator, battery, and all fuel parts (I have stock mechanical fuel pump).
Any and all responses would be very very appreciated,
thanks a whole lot
brad

 

Take a look at the plug on the back of the ignition. You will probably find that it is LOOSE and that is the problem. Pull it back onto switch.

My '69 did the same thing. I dont thing Ford put anything to hold the plug in the back of the switch. If it wiggle loose, it will DIE. It will also only RUN with key to START.

I went thru this a few years back. Boy did it throw me for a few loops til I figured it out. Now I find myself reaching up under dash occasionally to see if has worked loose.

I about went bananas at the drag strip one day when it did this and I about tore the truck apart trying to figure it out. I just happen to reach and bump plug....Vroom.....it started right up and stayed running.

I hope this is it.
Good Luck
Larry

 

Thanks a lot for the response. I made two mistakes in my original post - I forgot to mention that i have a new ignition switch and I DON'T have a new distributer.
I did what you said and felt around the switch and pressed in the wires. It still wouldn't start, and nothing was loose so I pulled out the switch and made sure everything was firmly in place and jiggled the wires around. Still would not start. So I pulled off the back of the switch (the plastic part that the wires are attached to and where the bullets fit into) I inspected it and everything appeared OK. So I put it back together and then the truck started up. So do you think that there is a problem with the switch itself even though it is fairly new (about 9 months old)? Do you know of any other parts that i should check out? I really don't think I did any thing to help the situation by just taking out the switch unless I jiggled a loose piece around inside the switch.
Thanks a bunch for the help
brad

 

If you have the wiring diagrams to know which wire to hook to start/run engine I would try it without the switch.

It sounds like a faulty switch. Maybe one of the brass wipers inside is not making contact. Since you wiggled it around it may work for awhile. I hope the switch is NOT one of those tiwanese models. Is it an original "used" one? or a real "new" one?

I dont think it has anything to do with under the hood.

Larry

 

In some models there is a ballast resistor that drops the 12V
down for the coil only in the "run" position. If this resistor is open, or the wiring to it, you will have the symptoms you are describing.

 

I have a new switch from autozone so more than likely it is cheap foreign crap. I don't have a resistor attached to the coil on this truck. (If I had a ballast resistor it would be attached right on the coil with a bracket, right?)
I don't have a wiring diagram for this truck. Does anyone else know what all the wires go to so I don't have to spend a bunch of time poking around?
thanks very much
brad

 

The ballast resistor is almost never easy to find. It is not visiable and my guess would be a ballast wire with the appropriate resistance. If you look I'll bet you will find that there are two small terminals on the starter solinoid. One is the terminal that energizes the solenoid. The other one marked I or IGN is the terminal that supplies 12volts to the coil and bypasses the ballast for starting. If putting a wire from the battery to the coil positive and trying to start the engine solves the problem it is the resistor. It is OK to run a ballasted coil for a few minutes on 12VDC.

 

Sounds as if the resistor wire has burned in two or has too much resistance within itself.

Joe

 

I've had this happen on two cars and believe it or not it was the starter solenoid. Engine starts fine but dies in the run position. What was happening was when the solenoid is energized the "I" terminal was supplying 12 volts like it should but then it was shorting to ground all other times. Weird failure mode, the "I" terminal should be floating at that time because it's connected to the coil +. In fact, you can measure your coil voltage from the wire on the "I" terminal, kinda convenient.

Barry

 

Ok, I was going to do some searching with a testlight and a voltmeter today but I noticed something else. I had removed the ignition switch from the dash and was just letting it hang down so incase it was in fact the switch that was causing the trouble I could hotwire it easily. Well I noticed that when I was moving around the switch I was bumping another wire that is not attatched to the ignition switch. Whenever I moved this wire, the ignition circuit would shut off like I described. This was a white wire that went to the fuse block to a 2 amp fuse (a really short one) This fuse was labeled as the fuse for the instrument panel. On the other side of the fuse there was a red wire. I did not have time to track down where they went. I pulled out the fuse and replaced it since I couldn't tell if it was still good or not. I have not had any trouble yet, but that does not mean I have fixed anything. So, do you guys think that there is a problem somewhere in the instrument panel???
Also, I do have a new starter and solenoid, and I had this problem both before and after I replaced it.
thanks to all of you for your great help
brad