MSD wiring

-
63SplitWindow

63SplitWindow

Well-Known Member
Joined
Nov 21, 2021
Messages
237
Reaction score
139
Location
Montgomery County PA
As previously poster, I am rewiring my 73 Dart with a Painless harness and I want to keep my MSD box. It was originally wired with a kill switch to the small red wire to the box, so you had to close the switch and hit the key to start it. Can I eliminate the kill switch and just wire the red lead to the start position? Or the run position?
Thanks,
Bill
 
63SplitWindow said:
As previously poster, I am rewiring my 73 Dart with a Painless harness and I want to keep my MSD box. It was originally wired with a kill switch to the small red wire to the box, so you had to close the switch and hit the key to start it. Can I eliminate the kill switch and just wire the red lead to the start position? Or the run position?
Thanks,
Bill
Click to expand...
As long as the battery connections are connected to the battery I don't see why not...
 
You can but you want a consent hot from the switch. Don’t want run or start as those circuits are not hot at the same time starting the car. Think like the radio wire, it’s hot with the key being turned on. I wired mine with a switch under the dash as theft protection…

I have to look on my car but think it is one of the wires 932,933,934 in this group.
 
Last edited:
j par said:
I'm sure the msd instructions say..
Click to expand...
ignition_logo_dia[790x].jpg


Not really
 
Scody21 said:
You can but you want a consent hot from the switch. Don’t want run or start as those circuits are not hot at the same time starting the car. Think like the radio wire, it’s hot with the key being turned on. I wired mine with a switch under the dash as theft protection…

I have to look on my car but think it is one of the wires 932,933,934 in this group.
Click to expand...

yep......932, 933 and 934 are the ignition wires.....but do I NEED the kill switch with the key swith?
 
I thought the kill was the white wire on a electronic pick up?
 
Big black..........ground
Big red..constant hot
Small red is like a relay trigger. It must be hot BOTH to start and to run

Your KEY SWITCH is the "key." The "run" line goes DEAD in crank
the bypass (usually brown, IGN2) comes from a separate contact on the switch and originally went to the end of the ballast which hooks to coil+. Hook the IGN1 and IGN2 coming from the key together and connect to the MSD "small red."
That same connection also feeds everything such as VR, alaternator field, etc. I WOULD TRIGGER A RELAY rather than leave the loads on the key
 
I'm failing to see what's not clear about the red wire going to the ignition switch?...
 
67Dart273 said:
Big black..........ground
Big red..constant hot
Small red is like a relay trigger. It must be hot BOTH to start and to run

Your KEY SWITCH is the "key." The "run" line goes DEAD in crank
the bypass (usually brown, IGN2) comes from a separate contact on the switch and originally went to the end of the ballast which hooks to coil+. Hook the IGN1 and IGN2 coming from the key together and connect to the MSD "small red."
That same connection also feeds everything such as VR, alaternator field, etc. I WOULD TRIGGER A RELAY rather than leave the loads on the key
Click to expand...

No longer a ballast resistor in the ign circuit and a 1 wire alternator.
 
63SplitWindow said:
No longer a ballast resistor in the ign circuit and a 1 wire alternator.
Click to expand...
You either didn't read or did not understand. YOU MUST tie the ign1 and ign2 together to get the MSD (or any other non ballasted ignition) to work, because IGN1 "run" GOES DEAD in crank, so you need IGN2 "bypass" connected to fire the thing during crank

HERE ARE THE ONLY outputs on a Mopar ignition:

ACCESSORY.........hot in either accessory or run, this obviously powers...."accessories"
RUN, IGN1, this is hot ONLY in run and goes DEAD in start. Runs the instrument panel, warning lights, and goes out into the engine bay, and powers the ignition, the alternator field, the VR, electric choke if used, and some smog doo dads on some models

BYPASS, IGN2....hot ONLY in crank, this goes out into the engine bay and connects to coil+ end of the ballast (usually brown) and provides THE ONLY power available to the ignition for start

START, often yellow.......goes to start relay to initiate starter. In '74, this goes through the seat belt interlock box. This contact on the switch mimics BYPASS but is a SEPARATE contact and is done to prevent circuit backfeed

YOU MUST connect IGN1 and IGN2 together, either at the switch or out in the engine bay and use that to power the underhood loads
 
67Dart273 said:
You either didn't read or did not understand. YOU MUST tie the ign1 and ign2 together to get the MSD (or any other non ballasted ignition) to work, because IGN1 "run" GOES DEAD in crank, so you need IGN2 "bypass" connected to fire the thing during crank

HERE ARE THE ONLY outputs on a Mopar ignition:

ACCESSORY.........hot in either accessory or run, this obviously powers...."accessories"
RUN, IGN1, this is hot ONLY in run and goes DEAD in start. Runs the instrument panel, warning lights, and goes out into the engine bay, and powers the ignition, the alternator field, the VR, electric choke if used, and some smog doo dads on some models

BYPASS, IGN2....hot ONLY in crank, this goes out into the engine bay and connects to coil+ end of the ballast (usually brown) and provides THE ONLY power available to the ignition for start

START, often yellow.......goes to start relay to initiate starter. In '74, this goes through the seat belt interlock box. This contact on the switch mimics BYPASS but is a SEPARATE contact and is done to prevent circuit backfeed

YOU MUST connect IGN1 and IGN2 together, either at the switch or out in the engine bay and use that to power the underhood loads
Click to expand...

Ahhhh......ok.
Thanks Dart
 
Yep like mentioned above you need to connect IGN 1 and 2 together.
Otherwise it'll just crank and crank from the key but no start. You will be able to start it at the starter relay but not the key.

And it may take you a month to finally figure this out...ask me how I know.
Good luck.
 
Well, this may shed some light on my issue. Not to hijack, but...

My small red trigger wire goes through a switch on a panel. Turn switch on, box (6 digital) lights up as it’s supposed to. Key in crank position, no lights, no start. Similar set up, no ballast resister w/1 wire alternator.
Hmmm...
 
You must log in or register to reply here.
-

Back
Top