Other way around. If this is a later-style module, WHITE goes to your existing hot-in-START circuit on the 'S' post of the starter solenoid, and you will need to find a hot-in-RUN circuit for the RED wire.

This is the coil connector that would have been used on the truck that all your new parts came out of. A points-style coil uses threaded studs and the wires slip on with small boots. A Duraspark-style coil uses snap terminals that the horseshoe connector holds on to.

You have three options as far as the coil is concerned:

1) Use your original points-style coil with the threaded studs. The wire that goes to the positive terminal of the coil remains unchanged. To connect the negative terminal, cut the horseshoe connector off at the end of the GREEN wire coming from the ignition module and install a ring terminal, then install it on the coil with a small nut.

2) Use a Duraspark-style coil and use the horseshoe connector. Keep the connection of the GREEN wire between the horseshoe connector and the ignition module the same. Assuming your horseshoe connector has a bare wire coming off the positive (BATT) terminal, cut the boot off the wire that went to the positive terminal of the old coil on your truck, then splice this to the positive terminal of the horseshoe connector. To summarize, the wire that originally went to the positive terminal of your old coil now goes to the positive terminal of the horseshoe connector. The negative terminal of the horseshoe connector is already connected to the ignition module.

3) Use an aftermarket coil rated for use with an external ballast. You would connect it as described in options (1) or (2) above depending on the studs coming out of the coil.

I do NOT recommend using option 1. A Duraspark-style or aftermarket coil will be wound such that the secondary voltage can be higher. If you use your original coil from your points setup, you won't get the full benefit of the upgrade. I've just listed it for completeness.

 

Ok..so if I WERE to use method two..I wouldn't use a canister style coil? I have the positive and "tach" wire that comes off the horseshoe..the po sent a duraspark canister style coil with it..so I guess this is all where my confusion comes from

 

I'm not sure what you mean by "canister" style coil; one could say they all look like canisters. Let me be clear on the options:

1) Points-style coil with the threaded studs originally used in your truck.

2) Duraspark-style coil that would have been used on the truck that the Duraspark guts came out of.

3) Aftermarket coil that could use either style of connections.

At the bottom is a picture of the connections on a Duraspark-style coil (this is an aftermarket MSD coil, but the top of the factory Duraspark coil looks the same).

If the seller sent you the coil that went with the setup, then it's very simple. Use option 2 which means:

1. Get rid of the coil that's in your truck now.
2. Put the coil that the seller gave you in its place.
3. Take the wire that used to go to the positive terminal of your old coil, and splice it to the wire coming from the positive terminal on the horseshoe connector. Until you do this, that wire should just be free hanging.
4. The "tach" connection of the horseshoe connector should already be running to the ignition module through a GREEN wire.
5. Snap the horseshoe connector onto the coil.

Once you do that, all you have to do is connect the RED and WHITE wires of the ignition module as we discussed previously.

Picture of an aftermarket coil with Duraspark-style connection:



Picture of the horseshoe connector installed to a Duraspark-style coil:



And finally, for reference, here is a factory-style points coil that should currently be in your '68 that you will get rid of. You will notice that the body is similar, but the top uses threaded studs.

 

What if the green wire is free hanging on the horse shoe too?

 

It's unfortunate that he cut that, because there is no reason to do that when selling someone a Duraspark setup. This also must mean your ignition module (or the harness connected to it) has a hanging GREEN wire as well. It's not a big deal, it just adds more work for you.

The GREEN wire that comes from the TACH (negative) terminal of the coil horseshoe connector needs to go to the GREEN wire of the ignition module, as shown in the wiring diagram. The ignition module has a 4-connector MALE pigtail attached, with ORANGE, PURPLE, GREEN and BLACK wires. Did he give you the mating FEMALE connector for this? That FEMALE connector would have a GREEN wire coming off of it. That goes straight to the GREEN wire of the horseshoe connector. Again, I'm not sure why the seller would have cut that, unless it somehow made it easier to remove.

Some advice: in automotive electrical systems, wire color is used to differentiate what different signals do. This is important because wires typically come out of something like a switch, then get hidden along their entire length in some sort of conduit or harness wrap, and then come out to their destination (such as a bulb, etc). If the wires were all the same color, it would be hard to figure out which wire was what at the end.

Therefore, if you have a GREEN wire hanging off of something, and another GREEN wire hanging off something else, chances are those two go to each other. In the factory configuration, wires never change color along their length (this is why it gets tough when a previous owner adds custom wiring). As such, two wires of the same color rarely have different functions. There are cases where that happens, but when it does, it's usually between two systems that are unrelated and would never cause confusion.

To make things even easier, the colors used on the actual truck are noted in many wiring diagrams - so you can cross reference what you're looking at on the truck to what you're seeing in the diagram. The wiring diagram is just a tool to help understand what colors run between which points. At the end of the day, wiring is all about colors.

You can also use the wiring diagram to answer your question. In wiring diagrams, lines are used to tell you what is connected to where. Looking at the wiring diagram, you see a line drawn from the TACH signal of the coil to the ignition module, and it is labelled GREEN. This tells you the TACH signal of the coil must connect directly to the GREEN wire of the ignition module. There are no other lines drawn off of that line or either end, so there are no other connections to make for that portion of the circuit.

 

Ok..I'm home and have looked everything over. On the horseshoe..there is 4 wires..a red one that is labeled "coil pos"..the green wire that runs to the module..then another green wire that comes off and is not connected that is labeled "tach" ..then there's a red short wire with a grey plastic rectangular plug on it.

 

Easy enough, here they are explained:

This will splice into the wire that went to the positive terminal of your old coil.

That's good, leave it as-is. THIS is the trigger signal from the module.

This would have literally gone to a tach. It's the same signal as the trigger from the module and hence the same color. If there is not a clean way to remove it, then tape it off (unless you want to use a tach).

This is for an ignition noise suppression capacitor. It's to help keep interference out of the radio. Just leave it; it does not need to go to anything.

 

FMC..you've been a terrific help. I haven't said thank you yet..but thank you. I know i've been a headache..but at least i've learned a little about engine wiring! haha So..the green LOOSE wire gets taped up unless i install a tach...should I find a way to connect the gray rectangle clip to the factory harness? or is it necessary? then everything else is self explanatory. Phew..we dug through that pile!! haha

Another thing..since I have the resistor wire..or should..then it SHOULD be okay to run an aftermarket coil? the factory harness hasn't been messed with as far as engine wiring goes..but i'll go under and look this weekedn.

 

No worries, glad to help. Your wiring harness does not have a place to plug in the grey rectangle connector, and neither would the donor truck's - the item into which it plugs (ignition noise suppression capacitor) is a small standalone piece. It is the silver can in the picture below. In this picture it happens to be tied to the voltage regulator (in blue) - this was another common location.



Again, it does not affect the function of the ignition and can be left off. If you never hear low-frequency whining in your radio, you do not need to worry about it. It was mainly a problem with early-model radios. Most modern radios have enough input filtering that they do not need to depend on the truck for this.

Aftermarket coils don't always require a ballast resistor. Some require a ballast resistor, some cannot function with a ballast resistor, some can work either way. You must retain the ballast resistor to protect the ignition module, so if you do replace the coil with an aftermarket version, it must be able to work with a ballast resistor in the circuit.

One such aftermarket coil that is popular with Duraspark owners is an MSD Blaster 2F coil. It is a drop-in replacement for the original Duraspark-style coil: Blaster 2 Coil, Ford High-Performance - 8205

My note about having to retain the ballast resistor is reflected in the coil's installation instructions as well. You literally change nothing except coils.

My personal opinion is that aftermarket "performance" coils by themselves are not worth the money. You are primarily paying for a brand name. "Higher voltage" or "hotter spark" is not necessarily a good thing. For a given plug gap, there is a specific range of voltage necessary to fire the combustion mixture. Much higher than that can burn up the plugs. There's no way to make voltage "better." Also, performance coils typically have a lower primary winding resistance than the factory coil, which pulls more current through the ignition module and stresses it. The ignition module is not designed to dissipate any more heat than it does under the factory setup, so any kind of punishment can actually cause it to wear prematurely. And since there are little gains in doing so anyway, I don't see the point.

 

Again..I've learned something now that I've tied up the loose ends and know what dead ends go where..it really is about just the red and whit wires. I've always tinkered with the thought of an aftermarket coil. I figured a "hotter" spark would burn excess fuel more completely and help in idle smoothness and better cold starts. As simple as it is to change them out..its nothing I can't do way down the future. My bud runs the blaster 2f and has had great luck..then again he also runs a built 302.. for simplicity sake I'm just gonna keep the original for now..its no biggie

 

Coil Specs...Basic Science or Just BS? Breakerless Ignition.

 

Read every word and soaked it up pretty interesting stuff..and makes a lot of sense too!!

 

Ok..sorry to pick your brains again..for the life of me..i can't find the pos coil wire to splice into my coil pos on my duraspark..ive searched the truck over and I can't find the wire that was on my coil pos...

 

Nevermind.answered my own question..found the wire!

 

I have scrapped and sanded and finally gotten my Igniition Module Box that rides on the drivers side fender well to were I can read it and come out with the same answer 5 times in a row. It is a D8VE-12A199-A2C with a blue grommet (Honest I just went out and checked again) However I cannot find this as the listed Square Ignition Module for any 1981 Ford F-100 302 anywhere on the internet. Not with a Blue Grommet. I bought this truck in the early 80's and it has never failed me. I want to replace this module or get a spare just in case.
1. Is this a Duraspark II or III?
2. If I replace it with a new one, I would think I can just plug in the RED & WHITE wired socket into that one, and the BLACK, GREEN, PURPLE, & ORANGE wired socket into the other one, just as it sits right now.

I get that it is best to stick with Motocraft as the best maker after all it has run for over 30 years on that specific square Ignition Module siting over my drivers side fender. What else should I do while I am in there?

When I purchased this truck it was entirely rebuilt by master mechanics even the transmission 3 speed on the floor with an overdrive. I try to do a little more upkeep every month.

Again Motocraft Duraspark Ignition module, blue grommet, red, white, black, green, purple and orange wires out the blue brommet. I find in Wikipedia That the Duraspark module was used by AMC starting in 1978 and continued to be used with AMC's Computerized Engine Control.

So I am confused. Is this a Duraspark II, or III system? It has the widely spaced distributor also on the truck.

I don't know if I am supposed to time this after replacing everything, or does the vacuum and timing all do itself through the computer?

Thanks for any answer motdranwod@gmail.com