Ignition relay wiring

n_reckless

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Hey,

I'm about to bypass the resistor wire for the electronic distributor.

I bought a Pertronix power relay kit and I'm trying the follow the instructions (https://static.speedwaymotors.com/pdf/4472001.pdf) but when I'm about to wire the isolation diode It says to split the wire from the ignition to the regulator terminal 'I'. It would be simple if I'd have wire at the terminal 'I' but I have nothing.

I have a disconnected black wire at the engine bay but I cannot figure out from where. (I don't know if this wire has any purpose because the car starts and drive excellent with a jumper from the battery to the coil...) What color the wire supposed to be from the ignition to term. 'I'?

I attached the photos of the voltage regulator and the wire what is not connected.





 
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Hemikiller

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Hook the Purple wire to the Red/Lt green stripe wire on the "I" terminal of the starter solenoid, that's the 12V boost line to the coil for starting. It has voltage any time the key is in start or run. You can simply put another nut on the stud of the solenoid, capture the purple wire eye loop and put the original wire back in place.

Large red goes to the Batt (+) stud on the front of the starter solenoid.

 

n_reckless

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I think there is a wiring diagram on the forum check above and see.
I already checked but the black should be a wire for the wiper motor. Probably the previous owner made some modifications and installed that wire. It also has a Duraspark ignition box with a regular distributor what I eliminated when I installed the ready to run dist.

 

n_reckless

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Hook the Purple wire to the Red/Lt green stripe wire on the "I" terminal of the starter solenoid, that's the 12V boost line to the coil for starting. It has voltage any time the key is in start or run. You can simply put another nut on the stud of the solenoid, capture the purple wire eye loop and put the original wire back in place.

Large red goes to the Batt (+) stud on the front of the starter solenoid.
So just hook the Pertronix purple wire to the terminal "I". And what about the diode?

The manual says "The isolation diode prevents current from the regulator flowing back to the ignition power relay when the key is turned of"

The MSD relay for the same purpose not mentions any diode.

 
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Don C

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Your car must be equipped with factory gauges and as such you don't have the alternator warning light and a wire connecting to the "I" terminal on the voltage regulator.

This leads to my question, do you have the factory tachometer? If so, it will no longer function, unless you run the coil from the bypass resistor wire and the Pertronix from the relay, or have Rocketman convert your factory 2 wire tach to a 3 wire tach. You can read more here

https://www.7173mustangs.com/thread-pertronix-and-factory-tach?

 
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Hemikiller

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Hook the Purple wire to the Red/Lt green stripe wire on the "I" terminal of the starter solenoid, that's the 12V boost line to the coil for starting. It has voltage any time the key is in start or run. You can simply put another nut on the stud of the solenoid, capture the purple wire eye loop and put the original wire back in place.

Large red goes to the Batt (+) stud on the front of the starter solenoid.
So just hook the Pertronix purple wire to the terminal "I". And what about the diode?

The manual says "The isolation diode prevents current from the regulator flowing back to the ignition power relay when the key is turned of"

The MSD relay for the same purpose not mentions any diode.


If you follow my method, you're hooking it to the starter solenoid, not the voltage regulator. I have my MSD 6AL wired like this and it works perfectly.

 

n_reckless

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Hook the Purple wire to the Red/Lt green stripe wire on the "I" terminal of the starter solenoid, that's the 12V boost line to the coil for starting. It has voltage any time the key is in start or run. You can simply put another nut on the stud of the solenoid, capture the purple wire eye loop and put the original wire back in place.

Large red goes to the Batt (+) stud on the front of the starter solenoid.
So just hook the Pertronix purple wire to the terminal "I". And what about the diode?

The manual says "The isolation diode prevents current from the regulator flowing back to the ignition power relay when the key is turned of"

The MSD relay for the same purpose not mentions any diode.


If you follow my method, you're hooking it to the starter solenoid, not the voltage regulator. I have my MSD 6AL wired like this and it works perfectly.
Got it, and it will probably work with the ready to run distributor too without the MSD ignition box.

 

n_reckless

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Your car must be equipped with factory gauges and as such you don't have the alternator warning light and a wire connecting to the "I" terminal on the voltage regulator.

This leads to my question, do you have the factory tachometer? If so, it will no longer function, unless you run the coil from the bypass resistor wire and the Pertronix from the relay, or have Rocketman convert your factory 2 wire tach to a 3 wire tach. You can read more here

https://www.7173mustangs.com/thread-pertronix-and-factory-tach?
Yes factory tach so it's likely won't work. I'm running MSD ready to run dist. and want to hook it up to the Pertronix relay.

 

TheRktmn

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Normally the diode in the 'I' terminal of the voltage regulator is to stop back feeding that can result in engine 'run-on'.

I include one in my Pedapter kits 'just in case it happens' but have never heard from anyone that they needed to install it.

 

n_reckless

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If you follow my method, you're hooking it to the starter solenoid, not the voltage regulator. I have my MSD 6AL wired like this and it works perfectly.
I forgot something. If I do how you hooked it up and connect the purple to the solenoid instead to the ignition, should I leave the ignition wire (what I supposed to hook to the purple originally) on the + side of the coil?

 

Hemikiller

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If you follow my method, you're hooking it to the starter solenoid, not the voltage regulator. I have my MSD 6AL wired like this and it works perfectly.
I forgot something. If I do how you hooked it up and connect the purple to the solenoid instead to the ignition, should I leave the ignition wire (what I supposed to hook to the purple originally) on the + side of the coil?
What does the electronic distributor manual say about power requirements to the coil?

 

n_reckless

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Solid 12V. And if I'll do your method connecting the purple to the solenoid instead of the ignition what's on the coil + now I have to do something with that ignition wire.

This is the MSD relay manual: https://documents.holley.com/frm33565_ready_to_run_add.pdf

I just chose the Pertronix relay because it's pre-wired. But pretty same wiring diagram.

 
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Don C

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What coil are you running, and what is the primary resistance of it? That is what determines the power requirement of the coil. It's possible to power the coil from the resistor wire and then supply 12 volts to the distributor via a relay. The electronics in the distributor provide a ground to the negative side of the coil, just like points, regardless of what the power input to the coil is. That way your factory tachometer will still work.

However, the relay has to remain energized on the reduced voltage from the resistor wire with the coil connected to it.

 
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n_reckless

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What coil are you running, and what is the primary resistance of it? That is what determines the power requirement of the coil. It's possible to power the coil from the resistor wire and then supply 12 volts to the distributor via a relay. The electronics in the distributor provide a ground to the negative side of the coil, just like points, regardless of what the power input to the coil is. That way your factory tachometer will still work.

However, the relay has to remain energized on the reduced voltage from the resistor wire with the coil connected to it.
I have a Blaster II with 0.7o resistance.

 

Hemikiller

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Solid 12V. And if I'll do your method connecting the purple to the solenoid instead of the ignition what's on the coil + now I have to do something with that ignition wire.

This is the MSD relay manual: https://documents.holley.com/frm33565_ready_to_run_add.pdf

I just chose the Pertronix relay because it's pre-wired. But pretty same wiring diagram.
In that case, then remove the original coil (+) wire, insulate and tape it out of the way. The only thing that circuit is being used for now is as a trigger for the relay. 

If you want the factory tach to work, you'll need an MSD 8920 tach adapter, or send it to Rocketman for conversion.

 
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