MSD wiring advice (connectors)

[cstreit]

Gang,

My MSD installation is going to happen this week.

Before starting, I am trying to figure out the neatest way to connect the thing into the system...

Presumably most of the wiring I need is in the CD unit plug. Since it's a high voltage system, tapping into the wires is probably not an option...

SHould I:

a) Use spade connectors pushed in to the existing CD female plug?

b) Cut the plug and solder the MSD unit in?

c) Use wire taps into the harness?

d) Re-wire?

e) Some great suggestion that you have, that I have not thought of...

[cstreit]

No one? I've read the FAQ and it' not helping...

According to a post I read a few days ago, I should have at least 30 opinions by now that aren't helpful.. (WHo WAS that guy anyway?)

[jluetjen]

Chris;
I just used "T" splices for splicing the connections into existing wires. In my case I also needed to connect to a ballest resister and the tach adaptor in which case I just used crimp-on blade connectors. I also had to use one to the diodes which I connected the same way. In all cases I tried to neatly insulate the connections with shrink-tubing or at least a neat electrical tape job depending on the connection. I haven't had any problems.

- John

[jluetjen]

BTW - Since the question always comes up about how to wire it; here is how I wired it into my '69E.



BTW: This was how I needed to wire it to get to work with my '69 model tach. Later model cars like Chris's 3.0 will be different.

If I remember my "Basic Electronics" course, the diode is to allow current to flow in only one direction.

[cstreit]

Is the green wire coming out of the side of the distributer the "trigger" wire?

What is the diode for? Is that to prevent circuit bleed and run-on?

[si2t3m]

Hi Chris,

Here is how i did the MDS box install on my 3.0L.

I figured pretty much that the CDI box (6pin) and it's wiring harness is seperated from the rest of the wiring harness.

I just put the CDI wiring harness in a box in case that i go back to a CDI unit.

Having removed the wiring harness left me with one problem. The shielded green wire coming out of the dizzy.

Lucky enough you can buy this wire seperatly. It has one end that goes into the dizzy and a nice 2 pin connector at the other end. Sourcing the right connector to go into this 2 pin connector might be a hassle but I think it's the same connector as the one used for the WUR (not sure about this)

Anyway, I was able to splice in my Magnetic pickup wires on the MDS to this wire green wire.

I ran a +12v wire direclty for the battery (easy to do in a 914-6).
I ran the neg wire to the chassis.

My switched +12v wire already had a connector (from the engine wiring harness). So i plugged my +12v for the CDI box on it.

Wire going to the coil go direclty from the CDI box to the coil.

I did have to cut the wire going to the tach. I put some spade connectors on it.

If i ever put back the CDI wiring harness i'll have to put a spade connector on the tach output where i cut it.

HTH

Marc-Andre Morin
70 914-6 conversion 3.0L Webers

[cstreit]

So I'm a tad confused here

I get the Power wires, Red Wire (switched), Black and Orange (To Coil) but still unsure on the "trigger"

I have a 3.0L with a stock dizzy... Which MSD trigger do I use? (White, or Violet and green) and where do they connect?

Sory if I'm being dense...

[tholyoak]

This is how I hooked mine up as posted in a previous thread: MSD Install Notes for SC

Installed the MSD 6 and blaster coil I picked up at Hershey this past weekend. Just thought I'd provide some notes for those
considering adding this onto their SC with the 6 pin CD box

I installed the box on the aluminum panel the original Bosch box was on. Installation was tight, it would have been much easier if I
didn't still have the original alt. with the external voltage regulator taking up space on the panel. I will post some photos if anyone is
interested. The coil mounted in the same bracket as the stock bosch coil.

I installed the MSD box by using spade connectors on the MSD leads and connecting to the original 6 pin connector so no splicing
into the harness was necessary and it can be easily switched back at any time.

A short lead was made to run from the tach output on the MSD unit and plugs into the 6 pin connector at terminal TD, no adapter is
necessary

The thin red wire is hooked to terminal 15 this is a switched 12V source.

The orange wire is connected to terminal A this is the positive coil lead (white wire for coil)

The black wire (thin) is connected to terminal 31-1 which is the -ve coil lead (brown/red wire for coil).

For the distributor trigger the green wire goes to terminal 7 and the violet wire goes to terminal 31d .This is important as if the car is
hooked up the other way it will run but very badly, ask me how I know

For the 12V power I ran the heavy red wire from the MSD unit to the +ve terminal on the starter, the heavy black ground wire is
connected to the ground lug behind the fuel filter and accumulator on the body.

[cstreit]

For the distributor trigger the green wire goes to terminal 7 and the violet wire goes to terminal 31d .This is important as if the car is

THe terminal numbers are not marked on my connector so I'm having trouble understanding your instructions...

What I'm looking for is this:

Off the MSD, there is a green wire, and a violet wire... Do these go to the Green wire coming of the distributor? If so, the green wire coming from the distributor has TWO wires in it... Which MSD wire goes to which distributor wire?

If the green wire coming off the distributor does NOT go to the green and violet MSD wires, what does?

From the wiring diagram, it appears that 7 is the "inside" wire coming from the distributor, and "31-d" is the "outside" wire...

[tholyoak]

The wiring harness connector doesn't have the pin #s on it, there should be a sticker on the side of the Bosch CD box showing the pin id. On my 6 pin box on my SC it is

Looking at the CD box the pins are

31/1 TD 31d

A 15 7


Therefore looking at the wiring harness connector should be

31d TD 31/1

7 15 A

The wire from the trigger in fact does have 2 wires in it and is the trigger used by the MSD and is hooked to the green and violet wires.

Todd

[cstreit]

Righty-o... That helps, thank you...

[si2t3m]

Hi Chris,

Just to mention that if you ever reverse the polarity when connecting the MSD box to the magnetic pickup you will end up with about 35deg of advance.

You will know right away that it's not ok. On my box, i had wired as per the instructions and even check on this BBS to see how others had wired it...

For some odd reason, my MSD box had the green and violet wires switched around.

HTH

Marc-Andre Morin
70 914-6 conversion 3.0L Webers

[cstreit]

THank you. I will pay attention to this then... 35 degrees of advance can't be very good for a motor for long... But must be QUITE noticable

[stevef]

I have been installing an MSD system in my 69 E with Webers and boy am I confused. I'm also installing a tach adapter and a pertronix ignitor system. I have searched the archives but now I'm even more confused.

Heavy Red and Black wires; no problem

Thin switched +12v red wire; I have connected this to the red wire that used to connect to the +ve side of the coil (isn't this a switched 12v source?) and to the red wire from the pertronix. I have spliced the tach adapter red wire into this circuit.

Thin white wire; Connected to the black wire from the pertronix with the white wire from the tach adapter spliced into it.

The orange and black wires from the MSD go to the coil. No problem!

I can't work out how to hook into the RPM transducer. At the moment the whole setup appears to be isolated from the tachometer. I have the old wire (black) that used to connect to the points on the side of the dizzy. Does this splice into the white wire from the MSD.

Hope someone can help me. I have studied John's diagram (jluetjen) but can't figure if I've got the switched source right or the tachometer input figured out

Thanks

[CamB]

I'm gonna open myself to attack for being wrong on two threads at once about the same thing...

Option 1 - if your tach used to be connected (black/purple wire) to a Bosch CDI unit, just plug that black/purple wire into the MSD 12v tach output on the top of the unit.

Option 2 - if your tach was connected to the coil (no Bosch CDI) use the MSD tach adaptor like the instructions say (red wire to switched 12v, other wire connected to you tach's black/purple and both connected to the white wire/points/pertronix one).

I think

[red-beard]

I think the correct wire is the black with purple stripe for the tach.

However, even with the tach adapter, it does not seem to work with the early 911 Tach. I sent my tach out to North Hollywood Speedo and they replaced the internals with something that works.

Checkout:

http://forums.pelicanparts.com/show...&threadid=75889

James

[CamB]

James

I saw your reply on the other thread too. Thing is (in contrast to your own experience, AND that on the other thread), I only know of one person who has installed an MSD on a 70s 911 and he just plugged it into the MSD tach output.

This is really weird.

Is there any chance you guys have hooked it up wrong, and NH or PA Speedo are just fixing the tach?

[red-beard]

I went as far as running a wire directly from the MSD unit directly to the tach. Did the same directly from the coil. Did this with and without the tach adapter. It didn't work. The person who "just hooked it up" may have had a later model tach. That is all North Hollywood is doing. They replace the internal tach board with one from the late 70's. Cost is about $120. Not a whole not more than the tach adapter!

I was very very frustrated last summer.

James

[Joe911]

OK – I have just spent way too much time figuring this out and am glad to share. Heavy Red off the common power pickup on the left rear fender
Heavy Black a good ground
Small black and orange to the new coil like John’s diagram

With regards to the tachometer hook up the 1969 911E and S and all 1970 models are unique. See the first figure from Up-Fixen, Vol. 11, p. 146.


Wire the MSD small red and white into the old CDI plug like my drawings. I have disassembled a nonfunctional Bosch CDI and intend to solder in the wires so I can just plug it in. For now I have spade connectors on the MSD wires temporarily attached to harness CDI plug. The Red/White wire from the coil to the Swithing SCR (intermediate unit in the first figure) is disconnedted and replaced with the signal from the distributor. See my drawing.

The MSD tach adapter can be spliced into the spade connectors where they plug into the CDI plug in the wiring harness like the third figure.

[CamB]

Yeah - I'm admitting defeat. Looks like the '69E and S tach setup is different to the one in a '72 and in my '69T.

FWIW, I had the insides of an SC tach stuck into my '69T tach to make it work with a MoTeC.