1978 F100 Pickup won't start

Rocky Fields, I replaced the starter less than two weeks before this problem began because the bendix on the old starter was sticking. I could drive the truck at low speed (idling) with no noise. I accelerated and the "very loud" grinding began. I went about five city blocks before I could find a place to turn around and bring the truck back home at an idle. It's a new ignition switch too.

Thanks for your reply. I appreciate your help.

__________________
The original point and click interface was a Smith & Wesson.
Nature, to be commanded, must be obeyed. -- Sir Francis Bacon

This is diagram I found for using Ford Duraspark module on garden tractor used for tractor pulling purposes. However it shows simplified way module is connected in an ignition circuit.



I just cant remember if Ford Duraspark coil has resistance built in or uses ballast resistor, or a resistance wire since I am using a GM module on my F250. A fusable link would have nothing to do with this resistance or so I would think. In this diagram it shows red wire coming from module to coil + terminal with ballast in the loop.

I am not suggesting you do this though I dont "think" it would harm anything, but if it were me I would run jumper wire from positive battery terminal directly to + coil terminal. Then try to start truck and see what happens. My guess is truck would stay running with key in run position. You cant drive truck like that but it would tell you that the wire (or ballast resistor if it has one) going to coil is bad.

I just dont think your problem is in distributor since truck starts with key in start position. Also not the ignition module since again it starts. Its only dieing in run position. So either bad wiring or bad ballast resistor if it has one. Ford wiring was well known for corrosion problems, thats why they were one of first to using dielectric grease in many of electric connections. Hey be happy that Ford put distributor on their V8s in front. GM and Chrysler put them back near firewall and you have to crawl into engine compartment to work on them.

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"What would you do with a brain if you had one?" -Dorothy

"Well, then ignore what I have to say and go with what works for you." -Eliot Coleman

Use a feeler guage. The only spec I could find is .025 to .035
Make sure you have it lined up properly. It's like setting points on a pre 1975
engine. Looks like you will have to set it.

Hey.

Did you address the possibility of a bad starter solenoid? This is usually located on the firewall...has starter and ignition connection.

RF

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RF, the starter solenoid was changed about three years ago. It hasn't been clicking or making any noise at all I have a brand new one I bought a while back in case the current one failed.

Hermit John, thank you very much for the picture. I haven't gotten that far with the truck yet.

Fixer, thanks for the picture of the reluctor wheel. That explains how to set the air gap.

I just got back from town. I bought a small wheel puller. I have to finish taking care of four houses of chickens before I can work on the truck. It isn't supposed to rain today so I should be able to get something done on the truck.

Thanks again for all the links, pictures, replies and help. I'll let you all know what I find out.

__________________
The original point and click interface was a Smith & Wesson.
Nature, to be commanded, must be obeyed. -- Sir Francis Bacon

I forgot to ask one question. At the parts store the guy told me I could spray wd-40 on the reluctor wheel to help get it off the shaft. Can I spray that, or Sea Foam into the distributor and not cause problems?

Thanks again.

__________________
The original point and click interface was a Smith & Wesson.
Nature, to be commanded, must be obeyed. -- Sir Francis Bacon

Thanks guys for bearing with me. You're good teachers and some of the best neighbors I've never met!

I'll get it whooped! I don't care how long it takes. I'll learn, and with you guys help, that truck will run.

Fixer, I've never gapped points, only plugs. When you say .025 to .035 does that mean any point between those two set points would work?

I just gaged the gap. The .025 feeler gage slides through with a little resistance. The .035 gage has more resistance. I didn't force the .035 gage too much but it will fit, just a lot tighter with more resistance.

__________________
The original point and click interface was a Smith & Wesson.
Nature, to be commanded, must be obeyed. -- Sir Francis Bacon

Set it at .025 and it does mean anywhere between .025 and .035.
Setting points is about the same procedure.
Now you can do it all.

I hope it fixes the problem. Having it run with the key in the start position has me bugged though. That tells me it may be the ign. module (brain).
I know it's new, but new isn't always good.
I've been wrong before.
See what happens with the new pickup coil. WD-40 won't hurt anything.

Sometimes desperate situations call for desperate measures. Are you will to do a little Rube Goldberg rigging to get this vehicle running? If so, here is what I suggest. Go to the link above http://www.wrljet.com/fordv8/duraspark.html
open this and then go near the bottom of the page and look at the schematic.
At the top of the schematic where the ignition switch is shown you will see on the right the Ballast resistor. On the side of the ballast resistor away from the coil temporarily connect a small jumper wire. Run that jumper wire to the positive terminal on the battery. Now get in the vehicle and start it and turn the ignition switch loose and see if the engine continues to run. It should. You will have to take the jumper off the battery to get the engine to stop. If all this happens the problem is either in the ignition or the Duraspark module. PS....IMO,since the vehicle runs in the start position there is nothing wrong with the distributor other than the possible pickup electronics. If your are not careful you will have the truck to where it will not run even in the start position.

__________________
Agmantoo
If they can do it,
you know you can!

Like in my answer, you are just bypassing the ballast resistor. If that lets it run, pretty good indication that the ballast resistor is the problem, not the ignition module, not the distributor. Course it could be wiring to/from the ballast resistor. I just wasnt sure that the original Duraspark coil had external or internal resistance. Your diagram indicates it has external ballast resistor. That and the corrosion problem in that era Fords is why I used a GM module in my F250. It eliminates need for resistance circuit altogether. Its also bit simpler to wire up and I like the HEI/TFI coil design better than a souped up points coil like Duraspark is. The GM module is just a better mousetrap than Ford or Chrysler or Bosch or various Japanese modules of that era. You really want a shock go price a Bosch module off a Volvo 245. Does exactly the same thing as the GM, Ford, or Chrysler module but costs like $250, thats how I found out these modules are all interchangable if you are willing to do bit of wiring. $250 and special order at that. Bosch is German for very expensive. The $15 GM is just the best design though you have to provide your own heatsink for it if not using it in GM or Fiat application.

__________________
"What would you do with a brain if you had one?" -Dorothy

"Well, then ignore what I have to say and go with what works for you." -Eliot Coleman

If I remember correctly you don't pull the reluctor wheel. Instead I think you have to drive out the roll pin and pull off the dist gear and then remove the shaft with the reluctor wheel. Check before you break anything or you'll be buying a reman dist.

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"Education is the ability to listen to almost anything without losing your temper or your self confidence"
Robert Frost

I know this is a little old now but did you ever fix it? I own a 78 F250 and I ended up having to replace alot of stuff on it to get it to run good.

mine did that, LOL

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I think that was dodge

__________________
http://lownfamilymaplesyrup.com/ max@lownfamilymaplesyrup.com
Professional Tool. 1220 Woodmere Ave,Traverse City, MI. 49686. 231-941-8003. http://professionaltool.com/

I have worked on a few of these old ford trucks and the first thing to check is a dirty ground connection from the battery to the engine. Remove the ground strap and clean the mounting surface. Good luck