MSD 6440 40th Anniversary 6AL Ignition Control Installation - Manual (Page 8)

INSTALLATION INSTRUCTIONS
M S D I G N I T I O N
• w w w . m s d i g n i t i o n . c o m • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • FA X ( 9 1 5 ) 8 5 7 - 3 3 4 4
Ballast resistOr
If you have a current trigger tach (originally coil
positive) and use the White wire of the MSD,
you can purchase a Chrysler Dual Ballast
Resistor (used from 1973 - 1976) and wire it
as shown in Figure 5.
eNgiNe ruN-ON
If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-
On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD
receives power directly from the battery, it does not require much current to keep the unit energized.
If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp
indicator and feeding the small Red wire even if the key is turned off.
early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag.
By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from
entering the MSD. Figure 6 shows the proper installation for early Ford and GM vehicles.
Note: Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed
facing the proper direction (as shown in Figure 6).
Ford: Install the Diode inline to the wire going to the #1 terminal.
GM: Install the Diode in-line to the wire going to terminal #4.
Figure 6 Installing the Diode to fix Run-On.
GM 1973 - 1983 with Delcotron Alternators
GM Delcotron Alternators use an internal voltage regulator. Install the Diode in-line on the smallest
wire exiting the alternator (Figure 6). It is usually a Brown wire.
1A-400V DIODE
TO CHARGING
LIGHT
SPLICE HERE
OR
DELCOTRON
ALTERNATOR
FORD VEHICLES
ATTACH DIODE TO
TERMINAL "1"
EARLY GM VEHICLES ATTACH DIODE TO TERMINAL "4"
1
2
3 4 SMALLER OF THE 2-WIRES
DIODE
WIRE LOOM
GM 2-WIRE ALTERNATORS
FROM POINTS
OR AMPLIFIER
MSD WHITE
MSD RED
SWITCHED 12V
(original coil+ wire from tach)
CHRYSLER DUAL
BALLAST RESISTOR
Figure 5 Wiring the Dual Ballast Resistor.