Posted By: 440challenger
msd wiring -stock harness - 05/04/09 01:55 AM
Hooking up a 6al on a 73 RR with elec ignition. I ran the heavy red to power,heavy black to ground, the small black to negative on coil,small orange to positive on coil, and the small red to the OLD coil POWER wire. Just making sure I hooked the small red up right...can anyone verify? Thank you!
Posted By: wingman
Re: msd wiring -stock harness - 05/04/09 02:01 AM
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.
Posted By: 440challenger
Re: msd wiring -stock harness - 05/04/09 02:17 AM
ok beacuse i wired it using msd's instructions for "chrysler electronic ignition using magnetic pickup trigger". Car has a msd dizzy installed too.
Posted By: wingman
Re: msd wiring -stock harness - 05/04/09 02:23 AM
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.
Posted By: 440challenger
Re: msd wiring -stock harness - 05/04/09 02:28 AM
If i recall the brown wire is the postive coil wire,so all i have to do i tag the blue into it...
Can't i just find a spot in the fue panel that has power when the key is on and in the run position?
Posted By: 440challenger
Re: msd wiring -stock harness - 05/04/09 11:30 AM
Ok,thank you for your help!!!
Posted By: 440challenger
Re: msd wiring -stock harness - 05/04/09 07:37 PM
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.
Posted By: 440challenger
Re: msd wiring -stock harness - 05/04/09 11:08 PM
to tell you the truth i never took notice to the key thing. My car always fires right up, I don't think i let off of they key but now you have me wondering
have to check it out when this rain gets out of here
Posted By: HealthServices
Re: msd wiring -stock harness - 05/04/09 11:35 PM
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.
Posted By: dirtybee
Re: msd wiring -stock harness - 05/05/09 12:12 AM
when i hooked up mine i followed the diagram for chrysler electronic ign. w/ magnetic pickup which has the little red connect to whatever was connected to pos coil feed. car ran great. after reading numerous posts saying the ballast can and should be bypassed, i just replaced the ballast coil thing in a stock resistor with a large gauge wire. guess what... car still runs great, don't really notice anything but the ign is now full power all the time.
Posted By: HealthServices
Re: msd wiring -stock harness - 05/05/09 12:23 AM
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.
Posted By: HealthServices
Re: msd wiring -stock harness - 05/05/09 12:46 AM
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?
Posted By: HealthServices
Re: msd wiring -stock harness - 05/05/09 12:54 AM
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
