Only the coil needs the lower voltage.

 

UPDATE:
The truck is running now!! I must have done something right with the wireing. I traced the red wire back to the '84 ECC (ECU, ECM, the book had several names for it in the wireing diagram) and there were two red wires going into it with one yellow constant hot wire along with a gob of others. One of the red wires when I ran a jump wire from the yellow to that red wire and started her up the battery voltage stayed at 14.08 even with keeping the engine at 2000 rpms and having the heater and lights on. So I turned her off and jumped to the other red wire and turned her on and the voltage at the battery was jumping around according to the load and rpms. So I cut the 1st red wire and hooked that up to a switch and ran a wire from the switch to battery positive.
However now Im confuzed because before no power to the box or coil and now even with the switch off theres power to the box and coil, occasionaly, and occasionaly I have to flip on the switch and start it up but then I can run with the switch off.

 

Im throughly confuzed now but at least I have my baby back, which makes me very happy, which makes my helper a.k.a my other half very happy. But I now have a new Duraspark II ignition box, ignition switch, and a shiny new switch on the dash... Keep getting parts like this and perty soon Ill have a whole new truck haha.
Thank you to all who helped and came up with Ideas and tests and troubleshooted, it is very much appreciated!!

 

Ok so yet another update:
I was having problems with the truck going down the road and randomly dying. So I got a ballast resister and installed that. What I did was I ran a wire from battery positive to a switch, from the switch to the ballast resister and then from the ballast resister to the DSII box and coil. So now they only have power with the switch on. However occasionally the truck will still die randomly and doesn’t always want to start now. It will crank over just fine but now is being very stubborn to start. And throws up through the carb more often then not instead of firing up.

I read that (at least on the 70’s Ford trucks) that there is a brown wire that acts as a coil bypass, it I remember right, that is on the starter solenoid’s “I” terminal. I don’t have an “I” terminal but I do have an “S” terminal that has a red wire with a blue stripe (I have an O’Reilly’s started solenoid) According to the Chilton’s book (76-86 P/U & Broncos) it says that that red/blue wire goes from the distributor/ignition module to the starter solenoid.

I tested that “S” terminal with the key on and it was .08 volts, and again while cranking and it measured 9.23 volts.
The truck did have the TFI ignition with the 300 when I originally got it and now has a 76 302 with the DSII ignition.
The last time I got her started I measured the voltage at the battery and it was 14.3 and then the voltage at the ballast resister that was 15.1 and on the other side of it was 12.3.

Questions:
-Is that voltage reading normal on the restister when its hardwired in like I have it?
-what would cause it to die randomly when its hardwired in? (the DSII box and coil were warm but not excesivly hot)
-why is it harder then heck to start?

 

You have the resistor wired in correctly, but I am not sure you have the ignition box wired correctly. You stated that you are feeding the coil AND the ignition box with the resistor. That is wrong. The resistor should only feed the coil, the ignition box needs the full 12v supply that you get BEFORE the resistor. So hook the box supply up to the input terminal of the resistor so it gets a full 12v(or whatever full battery voltage is).

Hard starting, especially when it gets colder outside, is usually caused by not having the resistor bypass hooked up. This feature gives the coil full battery voltage during cranking only. You are correct, in the older trucks this was provided by a solenoid that had 4 terminals, 2 large ones and two small ones. One small one is labeled "S" and the other small one was labeled "i". The "i" has 12v on it during cranking only, and this terminal was tied to the coil + directly. The newer trucks(around 80-up) did away with the 4 terminal solenoid, and instead they had a extra set of contacts in the ignition switch that did the same job. Since you are hardwiring everything, you have lost this feature. You need to go buy a 4 terminal solenoid, or if you are making all your own switches, and have a pushbutton starter switch, you need a double pole pushbutton switch, and then you can use that to supply 12v to the coil during cranking.

The wire that you are seeing in some of the diagrams going from the "S" to the ignition module, is the start retard wire. The ignition module has a special wire on it, that when it receives 12v, it sets the timing back to the engine a set amount. This makes the engine easier to turn over, especially during hot summer days when the engine is hard to crank. This also helps if you are hotrodding the engine, and have the timing set up a little bit advanced. Setting the timing a little bit ahead of what the factory recommends can give more power and fuel economy , but can also make it hard for the starter to turn it over.

 

Thanks Franklin2.
Today I went to the parts house and bought a 4 terminal starter solenoid and ran a wire from the “I” terminal to the coil positive wire (I have the plastic horseshoe on the coil).

Good news:
The truck started up just like the good old days.

Bad news:
I measured the voltage at the splice and at the “I” terminal. There was 8.7 volts were the coil positive, “I” terminal, and ballast resister wires came together. And also 8.7 volts at the “I” terminal… Isn’t that back feeding into the starter solenoid? And if so that’s bad right? … or is that normal? I didn’t think that was normal.

Solution if not normal:
I could run a wire from the starter solenoids “I” terminal to a toggle momentary on switch. That in theory would stop the back flow of current to the “I” terminal. Then from the switch to the coil positive wire… oh I got it; inline fuse?…. ok it sounded better in my head when I was thinking about it.

Or should I just leave it the way I have it; wired directly to the coil positive?

 

Yes it is backfeeding into the solenoid, that's why there is a separate terminal on the solenoid. I think you are slowly getting it. It's wired up fine and working correctly.

If you think about it, you want 12v directly to the coil during starting. You could easily get this from the "s" terminal of the solenoid, since it has 12v from the keyswitch during cranking only also. The keyswitch sends 12v to the "s" terminal when you spring the switch over to start, and then the 12v leaves the "s" terminal when you let go of the switch.

But if you connected the coil to the "s" terminal, the coil would get 12v during cranking, but when you let go of the keyswitch, your 8.7v would backfeed to the solenoid "s" terminal, and the solenoid would stay energized, and the starter would keep cranking and cranking till you got rid of the 8.7v(turn the keyswitch to off).

That's why they installed a separate "i" terminal. When the solenoid is activated, there is a contact inside that puts 12v on the "i'. When you let go of the keyswitch and the solenoid drops out, the contact pulls away from the "i" and any voltage that happens to be on the "i" after that has nowhere to go, it dead ends on the "i" terminal and does no harm to anything.

 

Alright I think I'm getting a grasp on electrical systems and electricity, lest on the Bronco.
A few weeks ago I ran into town and the truck died twice just in a 3 mile stretch. After I coasted into a parking lot I tried to fix it and troubleshoot the issue but to no avail. The DSII box and coil were not hot, warm, but not hot. I finally got it started but only ran for maybe a minute or so then died again and didn't want to start. So I found a tow home and just let it sit in the driveway for weeks.

Tonight I ran another wire from the "i" terminal on the starter solenoid to another switch, then from the switch to the white wire on the DSII box. With the switch on while cranking it starts up quite easier now even frozen cold (its been 20's-30's, touching low 40's that past few weeks here).

The Bronco ran fine while it was warming up then once it was almost to operating temperature the rpms started jumping around between 500-1200 and at times the rpms dove down to below 500 and acting like it wanted to die but just couldn't quite die
Then after it got up to operating temperature, the rpms stabilized at 800-900 like everything was normal.

Even though it sounds like the problem is fixed, or almost fixed, I still don't trust it. What would be causing the rpms to jump around while its warming up?

 

Why did you do this? The white wire on the module goes to the "s" terminal of the solenoid, there is no need for a switch. And all the white wire does is tell the module the engine is cranking, so the module retards the timing a set amount so the engine turns over easier. This problem arises more in the summer time when the engine is hot.

When it quits on you again, are you sure it's a spark issue? I know you have been messing with the wiring all along, but what's the possibility that's not the problem now, and you maybe have a carb/fuel problem? Have you done any checking when the engine stops on you?

 

Ok So I took out that switch, putting it in was a retarded move on my part. I also took my volt meter to the wire that was hooked up to the white wire on the box while cranking and while running (the same wire that Ive had it hooked up to for years now that is in the wiring harness) and found out there was no power going to the white wire. So I just caped it off and taped it. So I think Im done with the wiring.

I did change the fuel filter and adjust the carb and (fingers crossed) it seems to be running ok now.
Hard to beleave it was just a small, simple filter and fine tuning the carb that was causing all of that... and I guess a new spark box helps too.

Thank you to all who helped, much obliged.