CDI wiring question

[Arne]

As I look into all things fuel and ignition related on my '72 T to try to pin down a persistent problem (thread here - MFI troubleshooting), I have spotted something unusual in the CDI/ignition wiring.

If I am reading the wiring diagram correctly, there are two braided ground leads from terminal D (the single spade terminal) on the CDI box that are connected one to the negative terminal on the coil (#1) and the other to the distributor, presumably the side of the body.

On my car, one is connected to the coil as expected, but the other is connected to one of the coil mounting bolts on the fan housing.

Now, I really have no idea how important this ground wire to the distributor body might be. But considering my issue and how difficult is it proving to track down, anything that is not totally "correct" is immediately suspect.

I'm guessing that I should move that braided wire to the dizzy body. Can anyone provide me a picture of where the preferred connection is?

[Arne]

More. The two braided leads have different size ring terminals, and are different length as well.

One has the small (M4?) terminal to fit the small stud on the coil. The other is sized to fit an M8 stud, such as the coil mount stud on the fan housing it is now attached to.

Looking at the distributor for possible M8 connections, the only one I see is the nut that you loosen to adjust the timing.

But the braided lead with the M8 ring terminal is not long enough to reach anywhere on the distributor body, at least not how it is routed.

The braided lead with the small ring is considerably longer, just kind of coiled up under the coil.

It is possible that I need to re-route the harness that these leads come from, perhaps low and behind the distributor. That would allow the large ring to reach the adjuster stud/nut, while still leaving enough for the other lead to reach the coil.

Or perhaps I'm way off base on this and what I have now is not a problem.

[AKAMick]

Had the same problem on my 70T finally saw it fitted to a timing chain cover stud sort of like this. not my distributor, but the picture showed me the general idea.

[stephers]

Those are bothe what are called " shielded " grounds, they are there to protect the signal within the wire that it is protecting from getting interference signals Don't think that this is your problem but who knows, maybe the signal gets muddled enough , usually it would act more like a bad missfire

[Arne]

So it doesn't matter much where they are grounded, as long as the ground connection is good. I can deal with that.

[edmayo]

The ignition coil has a blu/yel. wire to term 15. Term 1 is a 14ga. brown wire from the coil term to the 8mm coil bracket attachment stud in the blower housing (one towards rear of car). One braided wire attaches to the 8mm coil bracket stud on the front side of the coil. (towards car front) The 6mm eyelet braided wire attaches to the chain housing stud right behind the distributor.

[edmayo]

picture may help.

[Arne]

Perfect, thanks Ed. I don't expect this has anything to do with my problem, but I want to touch all the bases.

Mine will look a touch different as the car had factory A/C and so it has the bracket that moves the coil farther counter-clockwise for rear condenser clearance.

[edmayo]

That's what it will take

[eaton]

Does it matter where the braided wire from CDI is grounded? Does it need to be grounded to the engine and coil attachment, or could you simply ground it to the body? Reason I ask is this thread made me take a look at my CDI box. And it has no ground from the CDI spade terminal. There's nothing connected to the spade. Runs fine. Perhaps it would run better with the ground?