Sorry that this is not for either of my Powerstrokes. It’s for my 88 6.6L diesel f600. I also posted it in the OBS forum to get more inputs. Sorry, I'm pretty desperate.
The truck has been reliably running till now. Suddenly it won’t stay running anymore and got stranded on a farm. The farmer will allow me to leave it there for a few days. It will start every time. As soon as I let the key go back to run position it dies. But, if I hold the key at start position, it will keep running and will even rev up if I step on the accelerate pedal. Based on these observations, I think that I can rule out the most common “air in fuel return line” problem. I took the switch off the truck and took it apart, cleaned all the contact points. I then connected it to the harness and use a small screw driver to manipulate it. Still the same, starts every time and dies. Without a spare ignition switch to test, I can’t be sure that a new switch will fix it and get it home. Before I get a new switch, I want to do some tests to make sure it’s the switch not anything else. However, I can not locate a wiring diagram for the ignition switch anywhere I looked on the internet. My last resort is the public library. I thought that they must have it in the All Data thing, but to my disappointment, they only have information up to 1 ton truck not mid-sized. So, I come here to see if any of you can help me get a wiring diagram, and or offer me you suggestion base on the symptoms and your general diesel knowledge. Thanks in advance and have a great day! Erwin

 

Most all ignition switches are the same. U have a start terminal and an Ignition terminal. If the switch is on, power should be on the I terminal. So a jumper wire would work to bypass the terminal on the back of the switch.

I am not familiar with your engine but most all engines then had a fuel shutoff solenoid off some sort. Google says yours had the case type that rod/cylinder thing that has 2 coils in it. A start/pull in coil and a run/hold in coil. The run coil sees more use and will quit more often than the pull in coil.

It looks similar to this.
https://www.google.com/search?q=ford...5QW79WcztiM%3A

If u have one that looks like that, there are two things you can do that may help.

With the key on, essentially stroke the rod back and forth several times. Sometimes they corrode from lack of activity and will not work. Giving it a HJ will knock that corrosion off.

If that does not work, check for power to that solenoid. There are 3 wires. One hot in start mode. one hot in run mode and one ground.

If none of the rest of that works, open the lever that solenoid attaches too and tie it back. That will turn the fuel on and let the truck run. When u get home, you will have to remove the tire for it to cut off. Older diesels had a cable on that lever than ran in the cab that you cut the fuel off and on.

 

rltonwebb vbmenu_register("postmenu_16491510", true);
Posting Guru
Thx for the quick tip. I did some more reading and found out that what you are suggesting is more likely than the ignition switch. I'll check it out tonight. Erwin

 

I cannot edit from phone but first post should have read "remove tie for engine to cut off" towards the end.

Obviously removing the tire would accomplish nothing. Lol

 

Does this truck have a transfer pump? If it has failed or the fuel filter has clogged, there may be enough fuel leaking through to start, but not keep running.

 

Carltonwebb, what you suggested is exactly on. I tied the lever to the engine block with a small rope and got her home. will decide what to do to fix. Might just go back to the good old mechanical cable setup. Thx all for your help. Erwin