HEI conversion extra wire?

Javarod · Nov 9, 2014

Ok, as noted elsewhere, i'm doing the conversion, and the web has been a big help, particularly this: http://goo.gl/VMGfl8 including a GM coil. Not sure it'll fix the problem, but its a good try. Now, on to the issue.

While i was working i found that the + terminal on the coil was fed from a wire spliced into the brown/I terminal on the starter solenoid.
Looking at http://www.mustangsteve.com/conversion.html it appears the wire is unnecessary in the conversion?
Or do i need to feed the new coil from it and not the red wire going to the Duraspark ICM (considering the gunk on the connector, that might be a good idea)?

The victim in question is an 86 Ranger with a carbureted 2.0 I4 in case that makes a difference.

RonD · Nov 9, 2014

The starter solenoid/relay wire "may" be needed, it depends on your other wires.

Quick how it works.
Older systems used a Ballast resistor to power the coil when engine was running, this reduced the 13.6volts(alternator voltage) down to about 8 volts, this lower voltage kept coil cooler.
The ballast resistor is on the wire coming from the ignition switch(resistor should be removed if using the HEI module).
Problem with ballast resistor setup is that when starting the engine, the voltage drops to 10volts while starter is cranking, so ballast resistor wire at the coil would be under 5volts, so very weak spark for starting cold engine.
The solution to this was to run a wire from the "I" post on 4 post starter relay, or from the starter motor post(with diode), to the "+" on the coil.
This gave the coil 10volts when cranking, and only when cranking, so hotter spark for starting cold engine.

What you need to check:
Does the wire coming from ignition switch to HEI module have voltage when key is in START position.
It will have voltage in RUN position, but some ignition switches cut that voltage when key is turned to START, because starter relay wire was used.
If your wire has voltage in RUN and START then you don't need the starter relay wire to coil "+"
If it doesn't have voltage in START then you do need it

Javarod · Nov 9, 2014

Thanks. If the diagram here ( http://www.fordmuscleforums.com/all-ford-techboard/479079-correct-duraspark-wiring.html ) is accurate, the ballast resistor is a non-issue as i tapped the red wire to the Duraspark ICM.

That still leaves the issue of the wire, so i guess we'll just have to see what happens, and use the wire if necessary. Or would it be safe to hook it in just in case?

RonD · Nov 11, 2014

Diagram in your link show Red wire(going to module) only has 12volts when key is in R(run) position
That 12v is disconnected when key is moved to S(start) position.

But just check the wire for 12volts in RUN and START, if it have voltage in both positions you will be fine.

You can hookup "the other" wire IF(big if) if comes from the "I" post on starter relay(solenoid).
IF it comes from starter motor's cable post then it needs a diode in line

HEI conversion extra wire?

Javarod

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RonD

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Javarod

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