Installing MSD6AL

[Dillon Crowell]

I am planning on installing this ignition system. I know I’m supposed to bypass the ballast just looking for help with which wires to use. I also have a wire running to a fan relay that someone wired into the blue/yellow wire. Where can I rerun this once I bypass it?

 

[Mattax]

The MSD doesn't care if the resistor is there or not.
Easiest thing to do is add a piggyback for the on/off wire.

See the original diagrams I've posted here
for points ignition.

6Al2 Box 12v Keyed source

I am trying to wire a 6 AL box into my 67 barracuda. I tried to wire it to an open fuse, like a tachometer, but those 12v sources turn off when cranking. I know everything works because i wired the small red wire directly to the battery to test it. Does anyone know of a keyed 12v source that...

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or here for magnetic pickup distributor (Looks like your car has one based on your photo)

Finding switched 12 volt source

I have to convert a 73 Duster from the OE ignition to an aftermarket box. Last one of these I did was 1999 or 2000. For the life of me I can’t figure out where I picked up the switched 12 volts to run the new ignition box. I also can’t remember if I just taped off the original coil wires or...

www.forabodiesonly.com

As far as the fan, my suggestion is ditch it and go mechanical if possible.
Blue and yellow without context I can't help with. If its a '73 and is the ignition branch to the ECU, I would find another power source. The J2 (ignition run circuit) is already heavily loaded in '73. But if the J2 is just being used to trigger a relay, as the photo shows it might be, then its fine.

 

[George Jets]

Use with an E-coil
Straight 12 volt to the coil, no ballast resistor required.

Runs Cool

☆☆☆☆☆

 

[67Dart273]

WHAT YEAR MODEL car are we working on?

Two of the wires are jumpered together, you can see the blue jumper at the one end


That is your "run" line. One of the other two goes to coil + and the other goes to the ECU which is not needed.

Find a wiring diagram, leave the wire going to the box loose, and jumper the other two together.

Now take your coil+ wire and use that to feed the "small red" of the MSD, which is an arming, or trigger wire

MAKE CERTAIN that you do NOT have ANYTHING connected to the coil except for the two coming from the MSD. No tach, no radio capacitor, nothing else.

Read up on your tach and the MSD as to what to do for your tach connection

 

[Dillon Crowell]

It’s a 74 valiant.so the blue wire coming in is the run, which wire is the switched power? The brown wire on the right side goes to the distributor. Which is the coil+wire?

 

[67Dart273]

It’s a 74 valiant.so the blue wire coming in is the run, which wire is the switched power? The brown wire on the right side goes to the distributor. Which is the coil+wire?

Can't you check continuity of a length of wire? Disconnect all 4. Disconnect the coil + (and the coil -) On the end of the ballast where the two wires are NOT jumpered, ONE of them goes to the coil (HINT!!!! will be the same color!!!) and the other goes to the ECU. Disconnect the ECU. That wire now will not go anywhere and you can check continuity to ground and anywhere else and it will be open.

So check the coil wire, and hook that ballast terminal to either of the ones that are jumpered, and that is all you need to do. You can even buy some male spade/ flag terminals, and just make a little jumper wire

 

[67Dart273]

It’s a 74 valiant.so the blue wire coming in is the run, which wire is the switched power? The brown wire on the right side goes to the distributor. Which is the coil+wire?

NO the brown wire on the right side DOES NOT go to the distributor. The "run" wire IS the "switched" power. But there is more to it. One n wire terminating at one of the ballast terminals comes in from the key in the start position, and provides 12V to the coil ONLY in start.

This here is from the 73 manual In this diagram, NOT on your car (the resistor may be positioned differently, you want the bottom right, J3 at the ballast, you want either of the two jumpered ones on the other end, and jumper those together. Disconnect BOTH wires AND THE cap and tach, if connected from the coil. Take the coil + wire and connec that to your small red MSD power trigger wire

 

[Mattax]

The ignition switch is the 'switch'. From the switch
J2 is engine run and on only when the key is in run. It has no fuse. It is not meant for heavy loads. J represents I for Ignition.
J3 is engine start and only on when the key is in start. It has no fuse. It directly supplies power to the coil during start.

With the MSD, power to the coil will come from the MSD orange wire in both start and run.
The MSD has a small red wire that must see some power to turn the MSD on. It can be connected to either the J2 or the J3 wire. It doesn't matter which as long as there is a connection between the two. The 1/2 ohm resistor is a good enough connection.
You can also join them together or jumper the 1/2 ohm reistor if you wish.

It can be done as shown here

or like this

Note: The heavy red wire battery connection is illustrative. It does not have to be at the battery terminal. It can be at the starter relay junction. In fact on a car with an ammeter (like your '74) it may be better off connected to the alternator. However its only 1 amp/1000 rpm so don't sweat it. Just make sure its a good connection.

 

[Dillon Crowell]

The ignition switch is the 'switch'. From the switch
J2 is engine run and on only when the key is in run. It has no fuse. It is not meant for heavy loads. J represents I for Ignition.
J3 is engine start and only on when the key is in start. It has no fuse. It directly supplies power to the coil during start.
View attachment 1716153180

With the MSD, power to the coil will come from the MSD orange wire in both start and run.
The MSD has a small red wire that must see some power to turn the MSD on. It can be connected to either the J2 or the J3 wire. It doesn't matter which as long as there is a connection between the two. The 1/2 ohm resistor is a good enough connection.
You can also join them together or jumper the 1/2 ohm reistor if you wish.


View attachment 1716153181

It can be done as shown here
View attachment 1716153184

or like this
View attachment 1716153188

Note: The heavy red wire battery connection is illustrative. It does not have to be at the battery terminal. It can be at the starter relay junction. In fact on a car with an ammeter (like your '74) it may be better off connected to the alternator. However its only 1 amp/1000 rpm so don't sweat it. Just make sure its a good connection.

So I can not use the ballast and tie the blue and brown wires to the red. If I do that should I just tie the yellow fan wire into the ignition run? I have a 4 prong ballast so just trying to figure out how it would be vs the 2 in the diagram
I plan on keeping the original stuff all there in case something goes wrong with it and I’m stranded. Sorry I’m new to wiring.

I also bypassed the ammeter.

 

[Mattax]

Sorry I’m new to wiring.

Well then the easiest thing to do is simply install a new ECU on the car. Halifaxhops collects old stock, tests if them if they are out of package and will sell you a good one. Also so far no bad reports on the new ones labeled HiRev 7500.

Weak points on the typical '74 electrical system are headlight circuit, seat belt interlock, and column connector.

I also bypassed the ammeter.

I assume this is not a Duster/dart sport with rear window defroster. Hopefully you did a good job on the connections. Some early 70s cars had leaks that did effect the wiring in that area. Not sure if that extended into '74. You've left yourself blind. A voltmeter tied into the switched power at the fusebox (accessory circuit) will provide some indication of the power supply operation.

I have a 4 prong ballast so just trying to figure out how it would be vs the 2 in the diagram
I plan on keeping the original stuff all there in case something goes wrong with it and I’m stranded.

OK. Then probably best to follow the MSD instructions for leaving the ECU connector in place, or at least making it easy to reinstall. Let me find that for you.

The reason for the the dual ballast is the original ECUs used a second ballast to control the current powering them.
The 1/2 ohm resistor did its usuall job of controlling current to the coil.
The 5 ohm resistor was for a second power connection to the ECU. Eventually Chrysler was able to change the internals so the ECU had a regulator inside. After that, the 5 ohm resistor and 5th wire was not needed.

1972 Imperial & Chrysler Ignition System Service Book (Session 292)

If I do that should I just tie the yellow fan wire into the ignition run?

No idea. We don't know what the yellow wire is. If you show us which terminal it connects to on the relay, then we'll know if it is the trigger or the main power.

 

[Mattax]

Let me find that for you.

The green and violet wires were spliced on, and that works, although I prefer splicing the proper connector onto the MSD twisted pair of violet and green wires.

The kits in the 80s and 90s came with some hardware to make it easy to convert back to factory ignition with two jumpers.

The point is to leave the original wiring at the resistors alone. Make the connections using the wires that originally went to the coil.

You can make yourself a terminal strip like MSD used to supply.
Here's my version on a E-core coil. Coil type irrelevant for the wiring. The coil positive wire was blue in '67. For your '74 its brown.

or you can do somehting like this. Just be sure to have all conducting surfaces insulated so they don't short if the wire touches ground.

 

[Dillon Crowell]

So if I unplug the original module I can just tie into the brown coil positive

 

[Dillon Crowell]

The yellow wire seems like it’s the switched, there is a bigger red wire coming into it from the starter relay which is the power.

 

[67Dart273]

The yellow wire seems like it’s the switched, there is a bigger red wire coming into it from the starter relay which is the power.

Yellow wire WHERE?? At the start relay? If so that is the START wire, and it only goes ONLY GOES to the start relay. That wire is in fact what activates the relay when the key is twisted to start. The remaining small wire is grounded by the neutral switch in park / neutral

 

[Mattax]

Yellow wire WHERE?? At the start relay? If so that is the START wire, and it only goes ONLY GOES to the start relay. That wire is in fact what activates the relay when the key is twisted to start. The remaining small wire is grounded by the neutral switch in park / neutral

First post he said its for an electric fan.
My suggestion was get rid of the fan, but barring that a relay done right could be OK.