Author Topic: Wiring in a MSD and need help  (Read 973 times)

Offline Kevin71

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Wiring in a MSD and need help
« on: October 22, 2011 - 11:05:55 PM »
71 challenger.  I got a MSD distributor and 6A control.  I previously had a electronic ignitior and replaced the wiring harness with a new one for the electronic ignition.  The color codes on the electronic ignition don't match with the orginal wiring diagrams.  The balast resistor has four prongs.  Two in two out.  I have a blue and brown to the balast that I am running to the red power line on the 6A control box.  There is also a green with red stripe wire to the balast and I don't know what that is for or where it goes.  The plug that went to the old orange ignition box has a green with red stripe wire in it.  But do have a green with red stripe wire further down the harness that  I assume would go to the horns or that is what the wiring diagram says it should go to.  The green with red stripe plug into the balast resistor and had a blue coming out on the opposing side.  Can't find a gray wire for the tach either.  Could it be the gray with black stripe wire that went to the coil or there is gray with black stripe to to the old distributor.  There is a solid blue wire that was connected to the coil that is probably a 12 gauge wire.  Then there is a smaller blue wire and don't know where that should go.  There is no blue with white stripe wire anywhere that is in the wiring diagram.  Yes I am lost to say the least.  Would anyone have a wiring diagram of the electronic ignition harness that would make sense out of all this?




Offline 422STROKER

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Re: Wiring in a MSD and need help
« Reply #1 on: October 23, 2011 - 08:52:40 AM »
All I could find was a 73 Harness diagram for the 4 prong ballast resistor.  Hope this helps.

Tom

http://www.mymopar.com/downloads/1973/73ChallengerA.JPG
Tom
12.77 @ 108.87 15" Street Drag radial tires 3.23 gear

Offline Chryco Psycho

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Re: Wiring in a MSD and need help
« Reply #2 on: October 23, 2011 - 10:22:00 AM »
the green wire from the other side of the ballast is the low voltage power feed tothe 5 th pin on the ECU generally unused as most new ECUS have 4 pins now

Challenger - You`ll wish You Hadn`t

Offline Kevin71

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Re: Wiring in a MSD and need help
« Reply #3 on: October 24, 2011 - 02:05:22 PM »
I think the most reasonable thing to do is go back to the orginal wiring harness.  I ordered one from yearone this morning. 

Offline Kevin71

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Re: Wiring in a MSD and need help
« Reply #4 on: October 25, 2011 - 06:52:49 PM »
Thanks 72 challorange.  Just what I needed.  One other question.  On the back of the alternator there is a power post then two male tabs which I take to be the field connections.  What is the small stud for.  Is it another field connection.

Offline 422STROKER

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Re: Wiring in a MSD and need help
« Reply #5 on: October 25, 2011 - 07:06:29 PM »
Should be 2 field connections and the battery feed to the starter relay, not sure about the little post?  Unless that is the battery feed?

Tom

That site has diagrams for the 71 as well on a different link.
Tom
12.77 @ 108.87 15" Street Drag radial tires 3.23 gear