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MSD Wiring #1506790
09/24/13 09:13 AM
09/24/13 09:13 AM
Joined: Jun 2006
Posts: 5,163
CT
GTX MATT Offline OP
master
GTX MATT  Offline OP
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Hey guys, I understand how to wire the MSD box, but my question is are you running your thick power and ground leads directly to the battery per the instructions? I don't like this idea, just looking for ways around this. Why does the box need power when the switch is off? This doesn't cause a drain?

Also, for the secondary power lead, I'm assuming you are running this to the 12V side of the ballast resistor, any trick ways to run this without hacking my harness (new engine harness). I don't particularly like wiring accessories to the 12V side of the ballast either because I burned it up once before.

And lastly, any ideas on bypassing the ballast resistor without hacking the harness?

I have some ideas but just looking for some more.


Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
Re: MSD Wiring [Re: GTX MATT] #1506791
09/24/13 09:32 AM
09/24/13 09:32 AM
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1 Offline
Too Many Posts
Challenger 1  Offline
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Cincinnati, Ohio
Got any other power points on your car that is supplied by a wire the size of your MSD power wire?

I don't think so? MSD pulls a lot of power at hi rpm, it needs to be run directly to the battery.

Re: MSD Wiring [Re: GTX MATT] #1506792
09/24/13 09:49 AM
09/24/13 09:49 AM
Joined: Jan 2003
Posts: 5,444
Indiana
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YO7_A66 Offline
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YO7_A66  Offline
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Indiana
My battery has the 8mm hex head screw terminals on the side. I wired my MSD directly to these terminals.


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: MSD Wiring [Re: YO7_A66] #1506793
09/24/13 10:41 AM
09/24/13 10:41 AM
Joined: Sep 2005
Posts: 580
North Carolina, USA
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Silverbullet2 Offline
mopar
Silverbullet2  Offline
mopar
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Joined: Sep 2005
Posts: 580
North Carolina, USA
Mine is hid inside the car. I ran a 10 gauge wire from the MSD to the battery post on the starter relay.

Oh and when I wired mine up the instructions said NOT to use a ballast resistor. I didn't.

Last edited by Silverbullet2; 09/24/13 10:46 AM.
Re: MSD Wiring [Re: Silverbullet2] #1506794
09/24/13 12:23 PM
09/24/13 12:23 PM
Joined: Jan 2003
Posts: 16,376
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dogdays Offline
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dogdays  Offline
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There's some sort of relay inside the box. The small red wire, when energized,, closes the relay and connects the box to the big wire. So the box is really not energized when the car is turned off, or for that matter any time you don't have sufficient voltage on the small red wire.

The Capacitive Discharge ignition does not use a ballast resistor. Leaving the ballast resistor in the feed for the small red wire may cause the relay to malfunction. Get rid of it.

R.

Re: MSD Wiring [Re: dogdays] #1506795
09/24/13 02:46 PM
09/24/13 02:46 PM
Joined: Jul 2006
Posts: 4,179
California
mickm Offline
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mickm  Offline
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California
i run mine from the starter relay as well...

Re: MSD Wiring [Re: mickm] #1506796
09/24/13 03:54 PM
09/24/13 03:54 PM
Joined: Jan 2003
Posts: 20,814
A collage of whims
topside Offline
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A collage of whims
As for the ballast resistor, what I do is make a wire that bridges the wiring connectors. That way the BR is bypassed, I don't have to hack the harness, and I can return to stock if I ever want to in the future.

Re: MSD Wiring [Re: topside] #1506797
09/24/13 05:12 PM
09/24/13 05:12 PM
Joined: Jun 2006
Posts: 5,163
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GTX MATT Offline OP
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GTX MATT  Offline OP
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Quote:

As for the ballast resistor, what I do is make a wire that bridges the wiring connectors. That way the BR is bypassed, I don't have to hack the harness, and I can return to stock if I ever want to in the future.





This is what I was thinking.

The relay in the box makes me feel better about this/makes sense.


Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
Re: MSD Wiring [Re: GTX MATT] #1506798
09/24/13 06:14 PM
09/24/13 06:14 PM
Joined: Aug 2003
Posts: 12,291
Kent, Wa
340SHORTY Offline
Truck Nut
340SHORTY  Offline
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Posts: 12,291
Kent, Wa
You could take the resistor coil out of the ballast and replace it with a good sized wire so everything looks stock.. Carry a spare ballast in the glove box in case of an MSD failure..


I am truckless..






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