Re: msd wiring -stock harness
[Re: 440challenger]
#306980
05/03/09 10:01 PM
05/03/09 10:01 PM
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Joined: Jun 2004
Posts: 3,380
St. Charles, MO
wingman
Uncreative Title
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Uncreative Title
Joined: Jun 2004
Posts: 3,380
St. Charles, MO
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Not quite. The MSD red wire needs to pick-up from 2 sources on a mopar. The ballast wire that is hot with key on, usually dark blue. On the other side of the ballast resistor you need to pick-up power during cranking, usually the brown wire. The blue wire goes dead while cranking causing no spark. The brown wire is hot in crank only and goes dead when the key is released from the crank posistion. You will find these wires, regardless of color, on opposite sides of the ballast resistor.
Pigtail them together, and attach to the small red on the MSD.
P.S. You can eliminate the ballast if you wish--it is no longer needed.
Last edited by wingman; 05/03/09 10:03 PM.
1969 Dodge Coronet Super Bee 383 A4
1970 Plymouth Road Runner 440 FC7 (sold)
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Re: msd wiring -stock harness
[Re: 440challenger]
#306982
05/03/09 10:23 PM
05/03/09 10:23 PM
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Joined: Jun 2004
Posts: 3,380
St. Charles, MO
wingman
Uncreative Title
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Uncreative Title
Joined: Jun 2004
Posts: 3,380
St. Charles, MO
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Yeah the MSD instructions don't include this info.
I found out the hard way when I hooked mine up and it only ran with the key in "start" and then died in "run".
This question gets asked periodically here.
1969 Dodge Coronet Super Bee 383 A4
1970 Plymouth Road Runner 440 FC7 (sold)
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Re: msd wiring -stock harness
[Re: wingman]
#306984
05/03/09 10:29 PM
05/03/09 10:29 PM
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Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
Quicksilver440
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,766
Central Valley, CA.
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Quote:
Yeah the MSD instructions don't include this info.
I found out the hard way when I hooked mine up and it only ran with the key in "start" and then died in "run".
This question gets asked periodically here.
Wingman is correct....thats exactly how I did mine. 
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Re: msd wiring -stock harness
[Re: 440challenger]
#306990
05/04/09 06:58 PM
05/04/09 06:58 PM
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Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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Quote:
i just checked how i hooked it up in my challenger years ago and the red wire is just hooked to a 12v source, i never tied the two ballast wires together etc. 
My friend has his hook up the same way, I could never get his car started but he always can. The starter will crank the motor over and as you release the key the motor will fire. 
There are some members here too that have it wired the same way and don't have a problem starting the car this way. But do note the motor is not getting spark during the cranking, it does get spark as soon as you release it though. If the motor is still spinning when the key is release it will start.
Hooking it up without the brown wire is not the way the factory or MSD recomends but it can start. I'm more use to the car firing during the cranking process, not when I release the key.
This is funny because when I tried to start his car I about kill his battery. I crank and crank waiting for the motor to fire.
He cranks and as soon as the motor gets speed he releases the key. It starts at that time.
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Re: msd wiring -stock harness
[Re: 440challenger]
#306992
05/04/09 07:35 PM
05/04/09 07:35 PM
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Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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It is possible the Brown wire does backfeed thru the resistor and into the Blue wire, this is if the the brown wire is still connected at the resistor or to the Blue wire with the trace. If this is true then the MSD may sense the voltage back fed in the wiring during cranking.
The easy way to see if this is true is to test the brown wire for voltage when the car is running.
Allen
Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first.
Life was a little easier when I was just a wrench.
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Re: msd wiring -stock harness
[Re: HealthServices]
#306995
05/04/09 08:32 PM
05/04/09 08:32 PM
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Joined: Apr 2007
Posts: 807
Toronto, Canada
dirtybee
super stock
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super stock
Joined: Apr 2007
Posts: 807
Toronto, Canada
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Quote:
In the configuration you mention both wires are hook up to the MSD. Remember the small red wire does not need much voltage. It just needs something to tell the main unit to turn on. Kind of like a relay.
The big red wire needs battery voltage at all times so you can hook that to the starter big wire or whatever as along as it has 12 volts all the time.
so are you saying it makes no difference if you bypass the ballast? it's just acting as a signal and can be a lower voltage? as in i didn't need to modify my ballast resistor?
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Re: msd wiring -stock harness
[Re: dirtybee]
#306996
05/04/09 08:46 PM
05/04/09 08:46 PM
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Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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no you did not. But it is a source of heat you do not need. Have you ever touched these things when they get hot?  Basically you mention you used the brown wire going to the ignition coil pictured above somewhere along 'A'.
See where it says Ignition 2 start? That is 12 volts to the coil only in cranking mode. The Dark blue wire Ignition 1 is hot when it is running but not 12 volts when cranking.
It feeds the power to the coil thru the resistor. Now get this if you tap the blue wire along 'B' without disconnecting the wires from the ballast, during cranking the blue wire will get voltage back fed thru the ballast from IGN2 but at a lesser voltage. Get it?
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Re: msd wiring -stock harness
[Re: HealthServices]
#306997
05/04/09 08:54 PM
05/04/09 08:54 PM
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Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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Remember your MSD does not feed your coil thru the small red signal wire. It feeds it directly thru the MSD unit itself. And the MSD is powered from the heavy red wire which is suppose to go directly to the battery source
Allen
Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first.
Life was a little easier when I was just a wrench.
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