Duraspark Harness (American Autowire)

[broncodriver99]

Hopefully this info will be helpful to someone.

I have been piecing together a Duraspark II conversion for my Bronco for a while. I have been through several junkyard harnesses trying to make a good one out of the dirty brittle wiring that is 20+ years old. I finally gave up and bit the bullet and ordered the American Autowire harness from Summit Racing https://www.summitracing.com/parts/aww-500918. It is a little pricey @ $103.50 shipped but I figure well worth it compared to the time I spent looking for and trying to make junkyard parts work. I chose it over the Painless harness as it was cheaper and doesn't involve spliced in repair connectors like the painless harness. I am impressed with the build quality and all of the connectors are OEM Ford branded parts. There looks to be plenty of wire length for custom routing. It also has a built in tach wire feed that goes all the way back to where the connections would be made at the firewall. There are 4 wires that come un-terminated. Red(+12v switched source) I figure the feed for the idle stop solenoid on my '73 should work fine for this, Pink(ballast resistor out) the original coil feed wire should work as it is the outlet side of the factory resistor wire, Yellow(Tach signal), and White(12V feed from starter solenoid I terminal) I will have to track down a place to pick this feed up.

I figure after wrapping it with wire harness tape or hockey tape and tracking down some OEM connectors for the wire terminations it will look like it was factory. Anyway, I hope this info is helpful to someone looking to do a Duraspark swap and looking for good wiring. Attached is a picture to give an idea of the wire lengths.

And a link to the wiring diagram. https://static.summitracing.com/global/images/instructions/aww-500918.pdf

 

[1sicbronconut]

I've often wondered about using that harness, I've used the Painless harness a couple of times and actually ordered one from Summit the other day for $159.00 it's a plug and play set-up deal.

 

[broncodriver99]

I've often wondered about using that harness, I've used the Painless harness a couple of times and actually ordered one from Summit the other day for $159.00 it's a plug and play set-up deal.

Cool. Maybe this one will fit the bill next time.

 

[broncodriver99]

The more I look at the wiring and think about how the system works the more I think that when interfacing with the factory Bronco wiring the White wire(Solenoid I terminal) can be capped and left disconnected or removed.

This harness is designed to be a stand alone harness with no factory wiring interface other than the switched 12V(Red), hence the need for the I terminal connection during cranking. When using the factory coil + wire to feed the pink wire of the harness the white wire becomes unnecessary as it is terminated in the same connector terminal as the brown wire which is fed through the harness from the coil feed wire. The coil feed wire would have 12v from the splice in the factory harness that feeds the 12v from the I terminal to the coil supply wire after the resistor wire during cranking and would have ~8-10V through the resistor wire when in the run position.

So, it appears when using the stock wiring(pre-electronic ignition) that only 2 wire connections are necessary to get the system up and running, Pink and Red. Hopefully someone will correct me if my thinking is wrong.

 

[DirtDonk]

Sort of.
The booster wire (Brown) is already tied into your Red w/green wire right there at the firewall, as you say. So that's fine for the coil.
But the White AAW wire is not for boosting the voltage to the coil. It's for a START signal to the ignition module.

Regarding leaving it capped off however, that might be fine and not cause any trouble. I don't believe the DSII modulators with the Blue grommet really need that start signal to work in most cases. Some modules did have a START-RETARD function to make it easier to crank the engine (especially when hot), but I'm not sure what the Blue boxes do with the signal.

You could try it without the White wire then, and see if it runs fine. But don't tape anything up and make it permanent until you've tested.
When I made my own harness I used both the Red and the White wires, but never tried without, so can't say what the result is.

Paul

 

[broncodriver99]

Sort of.
The booster wire (Brown) is already tied into your Red w/green wire right there at the firewall, as you say. So that's fine for the coil.
But the White AAW wire is not for boosting the voltage to the coil. It's for a START signal to the ignition module.

Regarding leaving it capped off however, that might be fine and not cause any trouble. I don't believe the DSII modulators with the Blue grommet really need that start signal to work in most cases. Some modules did have a START-RETARD function to make it easier to crank the engine (especially when hot), but I'm not sure what the Blue boxes do with the signal.

You could try it without the White wire then, and see if it runs fine. But don't tape anything up and make it permanent until you've tested.
When I made my own harness I used both the Red and the White wires, but never tried without, so can't say what the result is.

Paul

What I am seeing in both the drawing and the harness itself is that the White wire is terminated together with the brown wire of the AAW harness in the same terminal/pin of the harness. That Brown wire is connected through the coil connector to the pink wire which is the coil feed wire that gets +12V applied to it during cranking from the I terminal of the solenoid and then has ~8-10V when the switch is released to the run position. Hooking up the White wire of the AAW harness only gives 2 different paths for the same +12V during cranking.

If this is wired up as a stand alone system where only a +12V switched supply is connected and an external ballast resistor is used like the drawing shows then the White wire would need to be connected to the I terminal. But, when using the factory Bronco coil + feed wire it becomes unnecessary as the stock Bronco harness already performs that function.

 

[toddz69]

Thanks for the report on the harness - looks like a great product for folks wanting to use Duraspark. I like how AAW seems to use a lot of factory connectors in their harnesses - that's one of my complaints with the Painless stuff.

Todd Z.

 

[Pa PITT]

...That's a great instruction sheet. Are there any more instructions sheets that would include the Battery, alt , & solenoid & starter.
.........
& a 3rd sheet to take the power to the ign switch.
... I got one I need to turn over . I'd like to heard it run .

 

[broncodriver99]

...That's a great instruction sheet. Are there any more instructions sheets that would include the Battery, alt , & solenoid & starter.
.........
& a 3rd sheet to take the power to the ign switch.
... I got one I need to turn over . I'd like to heard it run .

Pa, you would have to use the factory wiring diagram for that.