MSD 6AL ignition box
I have the box power wire running off of the old coil +ve wire as outlined by the instructions. The brown and dark blue wires are still run through the ballast resistor.
MSD uses a "trigger" wire which causes the box to power up, this is the "small red," and draws little current. As someone mentioned above, your original switched "ignition run" and the brown "bypass wire" need to be hooked together, in other words, all wires originall hooked to the ballast need to be jumpered/ junctioned together. THEN your original coil + can go off to the small red trigger wire.
The "main" box power --the wire which actually powers the box is the large gauge red wire, and is supposed to be hooked to a good big live power source such as the start relay. In the chart below (out of the destructions) it's called "HEAVY RED"
If you are getting LESS THAN 10V during cranking, either you have wiring issues, wired wrong, bad / dead battery, or your meter is AFU. A good battery during cranking should deliver closer to 11V.
The destructions:
[ame]http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/Ignitions/6420_instructions.pdf[/ame]
How and what do you have the distributor wired to? The coil? Make sure the WHITE wire is unconnected and taped off
You have a tach? How is it hooked up? Do NOT hook your tach to either coil terminal.
You should have your Mopar distributor hooked to the green and violet, and on page 10, you can jumper across those two to check for spark.
Make CERTAIN that you have not reversed the orange and small red. Orange goes to coil +
Sounds like with a Mopar dist. you should be using the diagram page 19