Duraspark/HEI swap help


lilbdfrd

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So I put a new/rebuilt distributor from the parts store in and wired in an h.e.i. module . The motor cranks but won’t start and I’m not sure what wire runs power to the coil. I have a purple wire going a few yellow wires connect to the coil plug in and a green wire to the coil plug in. Any help to get spark/ power to hei would be great
 


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RonD

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So you have a Duraspark distributor, won't work with TFI distributor

And it is wired like this: http://www.carbdford.com/tech/HEI/hei2.gif
To the distributor and HEI module

And you are using key ON full time power on Red wire
Back in 1984 there can be 2 ignition wires, one has power with key on but NO POWER when cranking, other wire has power when cranking but NO POWER key on.
 
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lilbdfrd

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I have a durspark distributor and the stock 84 coil. I don’t have the red wire hooked up to the coil. I have a purple wire that goes to yellow to the coil.i have the HEI module wired like the diagram. It had spark before I tore the computer wiring out and now it don’t.
 

RonD

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Up to you on what wire colors you use, but must be wired as shown in the drawing, 3 wires to Distributor, 2 wires to coil, + and - matters on the coil and HEI module

You don't need any of the computer wiring, but you do need a key on power wire, hooked to the Coil + wire which also powers the HEI module via its wire to coil +
Look for a Red/light green stripe wire, that should have power key on
Thats the only wire you use from the old spark system
 

lilbdfrd

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Thanks for all your help. I found a red wire with green strip it come from the main harness to another plug in. Not the main 6 wire plug in I’m just not sure what to use🤦🏻‍♂️.
 

8thTon

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An easy way to boost a Duraspark system is to use a TFI coil with it. I did this years ago on a full-size Jeep 360 with a Ford Duraspark ignition - it made a huge improvement.
 

lilbdfrd

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So ditch the stock 84 coil and get a TFI ?
 

8thTon

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So ditch the stock 84 coil and get a TFI ?
The weak part of the original Duraspark system was the can-style coil, but looking at RockAuto it appears Ford was already using the open frame TFI-style coil in ‘84, so my comment is incorrect. Doubt you’ll see any improvement from using the HEI module.
 

lilbdfrd

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So is the yellow wire on the coil the “hot” and green the ground wire?
 

lilbdfrd

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The weak part of the original Duraspark system was the can-style coil, but looking at RockAuto it appears Ford was already using the open frame TFI-style coil in ‘84, so my comment is incorrect. Doubt you’ll see any improvement from using the HEI module.
Im sure I have the tfi style coil , you can see it in my picture.
 

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So is the yellow wire on the coil the “hot” and green the ground wire?
Yes, that can be the case

But its usually Red + and Green -

Not familiar with yellow being used as +, but never had a 1984 Ranger

And just FYI coil "-" is not a ground per say it is the control signal that sparks the coil
Coil gets 12volts with key on, on "+" terminal
The distributor/module connect and disconnect the "-" terminal to spark the coil, it sparks every time it is disconnected
"-" is used because when there were points inside a distributor it was just easier to use "-" than "+" because of possible shorts
The points connected and disconnected "-" on the coil
This type of Electronic ignition just replaces the points opening and closing with transistor opening and closing to cycle "-" terminal on the coil, so no moving parts to wear out, although these can wear out, :)
 
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