MSD wiring help needed

[Yellowbird RS]

After reading several posts, and consulting the "101 Projects", everything was clear. But as soon as I see my old car wiring, it all seems so different and difficult. I need step by step instructions to connect the MSD 6AL in my car.
a) My old Bosch CDS has a three pin connector (white, red, white).
b) My coil has a strange connector, from which two cables come out: onee is brown and goes to the "earth" that holds the coil base. Another one is yellow, and joins in a point with a white cable which apparently comes from the MSD. A blue-red cable that comes from the distributer, and all of them get finally together in a black cable connected to the same coil base (earth).
Please I need advice step by step.

[emcon5]

And your car is a.....................?

[Nitrometano]

Also take a picture of the cables.

[magic930]

I used the following instructions, my car was an 87 930, not sure if yours will be exactly the same

1- The large red wire goes to the battery or Pos on the starter.
2- The large black wire goes to a ground.
3- The small orange wire goes to the Pos+ side of the coil.
4- The small black wire goes to the Neg - side of the coil.
5- The small red wire goes to a switched Pos + (red/white stripes)
5- The white wire is not used.
6- The violet wire to the shield of the green distrubutor wire
7- The green wire to center conductor of green distributor wire

(6 and 7 might vary depending on the year and distributor)

Tach adapter:
1- The red wire is to switched Pos + (red/white stripes)
2- The black wire is to ground.
3- The white wire goes to the tach output on the MSD unit.
4- The violet wire is run to the tach input (the purple and black wire by the CD unit).

[Yellowbird RS]

Originally posted by emcon5
And your car is a.....................?

A '74 Carrera (USA Specs.)

Originally posted by Nitrometano
Also take a picture of the cables.

[Early_S_Man]

This thread may be useful:

Perma-tune CD or Bosch CD?

That coil appears to be one of the rare Bosch 0.221.121.006 CDI coils. Terminal 'A' is positive, and terminal 'B' is negative.

Your 'white' wires at the CDI connector are faded. Look at the black bakelite connector body on the CDI unit ... labeled 'A', 'B', and 'C'. 'A' is the output terminal to the 'A' terminal on the coil. 'B'is +14 Volt power lead. 'C' is trigger lead from the distrtibutor. Terminal 'D' is labeled on the magnesium housing of the CDI unit, and is the ground or negative terminal of the CDI unit.

I will leave it to you to decide which MSD wires attach to the above terminals.

[Rex Walter]

Disconnect the negative terminal from the battery. To allow better access to the ignition unit on the left side (drive side) of the engine compartment, remove the black plastic cover from the ignition rack, the air pump, air filter housing, and the two warm air heater hoses. Additionally I removed the distributor cap and moved the spark plug wires out of the way. There are only three wires going to the original CDI unit, two white wires and a red one. Of the two white wires, the one goes to the + coil (or transformer) terminal, and the other white wire goes to the distributor points and the tach. The red wire is +12 volts switched through the ignition switch on the dashboard. Each of the white wires is wrapped with a grounded shield that is connected to the CDI unit case at one end, and the + coil white wire ground shield runs to the – coil terminal and is grounded on one of the posts that the coil mounts on, the other white wire ground shield is grounded on the engine near the distributor. All these wires can be removed as a complete harness, unplugging from the coil, unplugging from the distributor, unplugging from the CDI unit, and unplugging a white plastic connector for the +12 volts switched through the ignition and the tach signal – just follow the red wire from the CDI unit to the white plastic connector. The red wire from the CDI unit also contains a small canister about an inch in diameter and two inches long. I believe my manual refers to this as an RPM sensor for the tach. Remove it along with the rest of the harness. Additionally remove all ground wire attachments that this wiring harness is attached to. Removing all these wires really cleaned up the clutter in my engine compartment.

Remove the three allen bolts that mount the CDI unit to the ignition rack, and remove the old CDI unit. Remove the two nuts that mount the coil to the fan shroud. Remove the old coil from the coil mount and install the new coil the same way the old coil was mounted (be sure to get a coil that can be mounted upside down). When mounting the new MSD unit, I used a ¾ piece of plywood to move it out away from the inner fender wall that was interfering with one corner of the new MSD unit. The plywood must be trimmed to fit the upper rear corner and to clear one of the mounting bolts for the ignition rack. I mounted the plywood using the original CDI allen bolts, and used the screws supplied with the MSD unit to mount the MSD box to the plywood.

The wire connections required for the new CDI unit consist of ground, +12 volts on all the time, +12 volts switched through the ignition switch, distributor points, + coil, and – coil. The ground wire can be connected to one of the bolts that mount the ignition rack, and the coil and points can be connected using the wires and connectors that are already attached to the new MSD. Remember the white connector left in the engine compartment from the old unit that consists of +12 volts switched from the ignition switch and the tach sender? The switched + 12 volts for the new MSD unit can be connected to the red wire side of the white connector. The tach can be connected by running a wire directly from the new MSD unit tach output, to the black and purple stripped wire side of the white connector. I connected the +12 volts on all the time to one of the posts on the engine compartment fuse box that had +12 volts on all the time. That’s all there is to it. Now fire it up and enjoy.

Rex

[Nitrometano]

You are posting very good info guys!!! Keep going!!

[RoninLB]

all imo

keep the MSD uncovered for better heat removal.
solder all connections.
use 10ga feeding positive from starter.

[Yellowbird RS]

OK thanks.
I alredy install the MSD, the car run almost like ran w/the old Bosch the only difference I notice is a smooth idlle.

[Nitrometano]

Another recomentation: Do the ignition rotor modification to remove the inner resistance and place a pice of wire, solder ir and cover with epoxy. Do a search on this. I do this modification to my car the last week and I notice an improve in performance.