My F700 shuts off sporatically while driving and now is stuck in my driveway. I replaced the fuel solenoid already and that was not it. When I hold the solenoid down manually it will start and run no problem. Also, I am not getting any power to the plug on the solenoid. I think it is either the ignition switch on the column or a relay somewhere. Does anyone have a wiring diagram for the solenoid/ignition? or any ideas of where to go next.

 

I dont think they even had a relay in the circuit. If it quits running randomly, then it's likely got a bad connection somewhere.

 

what year is this truck? which engine?

 

Its a 1987 with the 6.6. I did look high and low for a relay, maybe thats why I cant find it.

 

If you want to throw a part at it for sake of reliability, go with an ign switch. If that's not it, then at least you have peace of mind. You could run a new 12 or 14ga wire from the ign switch or fuse panel for testing purposes.

 

went to order a new switch through ford. they told me it may be the relay. come to find out there is one mounted up under the glove box, of all places. took it out and it looks like it may be burnt on the power terminal. i will have a new one tomorrow. its not an exact replacement (discontinued) but the new one has instructinons on how to wire up correctly. we will see. THANKS FOR YOUR HELP GUYS! i will let you know how i make out!
Russ

 

I may have a few ideas if that don't work

 

If it is like the F700 I helped a fellow with there are two really weird looking relays on the top of the firewall. One is a start relay, the other is a run relay. One is powered when ever the key is on, the other is powered while cranking. The fuel solenoid works the lever on the side of the injection pump. It has three positions, off, run and start. What I did was use a Bosch relay in a fog lamp kit to replace the bad run relay on the truck, that was 5 or 6 years ago.

 

Well, I put the new relay in that Ford sold me. It started right up with no troubles. I am taking the truck out tomorrow for a 60 mile run. I will keep everyone posted. Thanks for all your advice.
Russ

 

Now that it runs, you can adjust the fuel screw and timing.

 

Many miles on it since the relay change. That was definately the problem. I would like to attempt to adjust the pump for some more power, she is very sluggish! I did notice that one of the bolts on the exhaust side of the turbocharger is missing and I should fix this before I start messing with the timing and pump. What do you think?

 

That's the fuel rate, and how easy it is to do.
Yes, you should replace the bolt, just in case exhaust starts leaking out from added fuel. Not a life & death thing to do, though. You can certainly do the screw & timing. The timing is almost identical to the DT466 in my other video. The difference being, you find your timing marks(about 13-15*), loosen up the 4 retaining bolts on the gear, then rotate the engine back to your desired advance(17-19*), then tighten it all back up. The 7.8's actually have a peep window like the DT466 to see the timing marks, the 6.6 doesnt, which makes it a little harder. OK, not harder, but more time consuming since it's the same process.
I get a lot of good reports of happy drivers after just the fuel adjustment on my Facebook page. I makes a nice difference, but nothing wild & crazy. That's another story.

 

Crank er up!

 

I think I have the same problem on a 89 F700 with the 6.6. It wouldn't start one morning and it's a first time every time sort of truck. Have changed the ignition switch at the bottom of the column and the starter solenoid. Have looked for a switch on the clutch but haven't found one. Now your text here suggests there is a relay for starting up under the glove box. How did changing yours out work.

 

you can buy a relay switch at most parts store for $10.you need to test which wire is power from the fuse box,a constant 12 volts weather the engine is running or not ,and which wire is power from the ignition switch ,12volts when the key is in crank and run position