It's back. Recently my pickup started unexpectedly shutting off, as if key was turned off. It used to do this before, then it quit doing it about a year ago.

Couple of curious insights: It will restart right up if you turn off the ignition and use the key to restart it. You cannot just rely on momentum to restart the engine. And, this happens about half the time I drive it and always within the first 1-10 minutes of driving. It has NEVER died after the first ten minutes; and it has NEVER failed to restart immediately when I use the ignition.

I seem to recall some old threads here that mentioned grounding wire(s?) to the control module and corrosion. WHICH wire(s) are the "usual suspects". Some mention hidden corrosion; do I just start probing to find weak wires?

Doubt ignition switch is problem (though that's exactly what it feels like when it dies); I changed the switch a long time ago because it needed help getting back to ON position anyway and hoped it would solve the dying problem (it didn't) The just went away on its own a few months later; now it's back.
Very irritating!

As always, your advice is much appreciated.
Thanks

Raul
w/ 81 F-100, I6, SROD, Carter 1V non-feedback carb, no A/C, no PS, no PB, but it gets me where I need to go

 

I had a similar problem on my 81 F-150. It would just go dead as if you turned off the key while driving. It could happen at anytime and at any speed, there was no set pattern. All i would do to restart while driving was to slip it into neutral and restart the engine. It turned out to be my control module. I replaced it in 1993 for $29 from Murray's (auto part store). It has never given me that problem again! And in fact to be sure, I put the old module back on and the problem came back. If you look at the underside of the module you'll see the epoxy sealant. When they go bad it is usually a thermo (heat) problem. They overheat and then shut down. Anyway, the epoxy on mine was a little melted.
I am the original owner of my F-150 so I know what parts are original. I got 12 years out of the factory module. If yours is still the original then i would highly suspect that to be the problem. One more thing, after i replaced the module i noticed how QUICKLY the engine fired up. No more cranking the starter. It still instantly starts up with just a quick click of the starter....
The module is on the drivers side front wheel well. Good Luck and let me know how it turns out.
-hooD
*************************
1981 F-150
Styleside 8'
4.9L 1 BBL Carb
C-6 auto trans
6100 LB GVWR Package
Limited-Slip Rear Axle
Stabilizer Bars Front & Rear
187,600 miles

 

I just had the same probolem on my'80 w/ 4.9l. I replaced darn near everything and it still wouldnt start. I even replaced the computer. And still nothing. So I went to the source for pwer, the battery. It wasnt that but one of the fuseable links coming off of thesolenoid had broken. I replaced it and it is running fine. It worked for me.

 

I was at the Ford dealer the other day and over heard them talking about this problem on late model fords. They go down the road and just shut off.. I think they said ford will recall some for this reason and they will be replacing the Module

 

 

I understand module recalls do not include 81.

Well, I half-way decided to replace module - after all, it works most of the time. But then I think, what if it fails when I pull out in front of a big loaded FORD Diesel, and my truck shuts off. I'm headed for the parts store, still having second thoughts. Half way there it dies, shift to neutral, start back up -- that does it, no more second thoughts.

I install the new module, it idles rough (coincidence???) - adjust the timing and it now runs like a champ.

But it will be a while before I am sure this was the problem (likely), as it has gone up to a year between failures. You do what you can and go with that. It seems solved.

Thanks for responses.

Raul
81 F-100, 300 I6, SROD, Carter 1V non-feedback carb, no A/C, no PS, no PB, but it gets me where I need to go

 

My truck had a similar problem, when you would turn on the headlights or heater it would die, Module was only 2 years old and a HD one at that, I've got a 1981 Ford one on it now, works like a champ, apparently most of the aftermarket replacements aren't of the same quality as the orig. parts, one of my neighbours carries spares in his truck, and mine had 2 in it when I got it...
Evan MacDonald
82 F100 FlareSide
HD 300-6, 240 head
NP435(6.69 low)
2.73 Geared 9"
Blue & Silver