Transcript Installation of the MSD 6 series Ignition Box

Installation of the MSD 6
series Ignition Box on the
1993 Ford Probe GT
V0.2 Beta
April 22, 2000
By: Mike Paszti ([email protected])
Photography: George Gebara
Contents
• External coil tower (the screw)
• Transistor hook-up, and MSD box hook-up
• Schematic
• Miscellaneous notes
What You Will Need
• MSD 6A series ignition box
• MSD or other suitable external ignition coil
• 3055 NPN transistor
• 1k resistor (1/4W or greater)
External Coil Tower
The external coil tower is a screw that is screwed into
the distributor cap so as to allow the high voltage output
of an external coil to enter the distributor in order to be
distributed to the cylinders.
The screw is driven through the cap so that it contacts the
metal strip embedded in the plastic. This strip is common with
(i.e., electrically connected to) the rotor inside the cap.
Epoxy is used to reinforce the screw and provide a secure
fit for the plug wire boot.
External Coil Tower
External Coil Tower
Metal strip runs internally
along dashed line
Epoxy
reinforcement
Screw with shaved
down head
My own repair (unrelated)
External Coil Tower
Transistor Hook-up
The transistor used in this project is a TIP3055 NPN transistor.
It is readily available at Radio Shack for a few dollars.
The 3055 transistor is what triggers the MSD box to fire a spark.
The transistor is triggered by the ECU.
By using the 3055, the internal ignitor module is completely
bypassed.
Transistor Hook-up
Ignore this diode. It is not required.
cut
cut
e
cut
f
cut
cut
f
e
a
c
b
d
C
B
A
Transistor Hook-up
The following wires are cut at the distributor:
-A
-B
-C
-e
-f
Connections to these wires are all made on the engine side
of the cut wire (not the distributor side).
Transistor Hook-up
Connect to ‘e’: Connection to ground. The ground wire ‘e’
can be identified by its all black colour.
Box white wire
Connect to -- MSD
‘A’: ECU requires this signal to operate
Connect to ‘B’(note 1k resistor): This is the tachometer signal
Connect to ‘f’: This is the trigger signal from the ECU. This wire will have a
coloured stripe on it.
MSD Box Hook-up
Thick Black Wire: Ground to frame
Thin Black Wire: To external coil ‘-’
MSD 6A
Thick Red Wire: To battery + or high
current fused line
Thin Red Wire: Ignition switch (‘C’)
White Wire: Connect to middle lead on transistor
Orange Wire: To external coil “+”
Schematic
Thick Black Wire: Ground to frame
Thick Red Wire: To battery + or high
current fused line
MSD 6A
‘C’
‘f’
3055
+
Distributor
Cap
-
External
Coil
1k resistor
‘e’
‘B’
‘A’
Miscellaneous Notes
• Mazda/Ford made subtle changes to the distributor between model years. In
some model years wires ‘A’ and ‘B’ are switched.
• As noted earlier, ‘e’ and ‘f’ are incorrectly identified in the Ford Service
Manual. If in doubt, the ground wire ‘e’ can be identified by its all black
colour.
• There appears to be some differences between the 1993 Probe GT tachometer
electronics and those of the Mazda 626/MX-6. This writer was unsuccessful in
making the tachometer work on a 1994 Mazda 626 with a MSD 6A BTM even
though the exact same set-up worked on a 1993 Probe GT. The MSD
tachometer adapter may resolve this problem.
•As noted earlier, regarding the wires that are cut at the distributor, all
connections are made to the “engine” side of the wires.
• The cut connections on the distributor side, particularly ‘A’, ‘B’, and ‘C’,
should be electrically insulated to prevent shorting.