'75. No spark, no power to coil.

[unclebilly]

Why is your coil so rusty?

[timmy2]

These guys make a new harness for you. Me too...
https://www.************.com/p-1853-cdi-wiring-harness-3pin-75-77-models.aspx

[Last911]

Originally Posted by unclebilly

Why is your coil so rusty?

Not my coil or setup That is a picture of timmy2's setup testing a CDI tester. I like how the system is isolated and all wiring visible as it relates to ignition.

I need a wiring layout like this!

[Last911]

Is this the barest minimum wiring I need for my car?

[ischmitz]

yes this will run the car

Not sure what (4) is. The tachometer connects to the green wire (points output)

[Last911]

Originally Posted by ischmitz

yes this will run the car

Not sure what (4) is. The tachometer connects to the green wire (points output)

Do I need any other grounds? (Ie Coil doesn't seem grounded except to CDI Box) and I'm assuming dizzy is always grounded to engine block? (Or do I need to wire up a ground?)

[T77911S]

yes dizzy is grounded to engine block.
I pulled mine and cleaned up all the metal to metal grounds starting at the points plate all the way to the dist shaft. it helped with the engine dropping out when I would set the timing and may have smoothed it out some.

you might ground the coil to the engine also.

[mysocal911]

Originally Posted by ischmitz

The box will have to release a spark when the terminal with the arrow is shorted to the housing of the box (GND).

As mentioned before, the three pin CDI produces a spark when the points OPEN.

Given your postings, do you really rebuild these units or do you send them to the
actual rebuilder, e.g. Pelican Parts?

[ischmitz]

Originally Posted by mysocal911

Given your postings, do you really rebuild these units or do you send them to the
actual rebuilder, e.g. Pelican Parts?

I actually invented them

[Last911]

She runs!!

The 'braided' wires were throwing me for a loop but they are not needed! You can simplify the wiring as per the diagram above and she will run! (The wiring allowed for a spark at the points when they were opened).

It didn't fire, but I knew the points were rotten, changed them. Ran first turn!

Thank you to everyone who posted and contributed, I learned soo much. I know what most of the wires in the engine bay are/do and alot of the fuses (don't ask).

[Last911]

Same issue again, are my points the issue?

[ischmitz]

Maybe the points need adjustment? Have you checked if they open and close properly?

[Jonny H]

Originally Posted by Last911

She runs!!

The 'braided' wires were throwing me for a loop but they are not needed! You can simplify the wiring as per the diagram above and she will run! (The wiring allowed for a spark at the points when they were opened).

It didn't fire, but I knew the points were rotten, changed them. Ran first turn!

Thank you to everyone who posted and contributed, I learned soo much. I know what most of the wires in the engine bay are/do and alot of the fuses (don't ask).

You really ought to keep the shield round the trigger and coil lines. You'll suffer misfiring if any EMI / ESD gets in the CDI trigger input.

Some ideas on your non start:

I don't see a ground strap on your relay panel. 3 pin boxes need cases grounded.

The simplest non start issue I've seen was where the trigger signal wire was grounded because the insulation had failed and was touching the case.

New points are very poor quality.. Check the plastic foot hasn't split where it is riveted on. Sorted through a box of around 50 new Bosch points last week, over half had a split.

[timmy2]

No shield for minor operational testing is ok. You need the shields long term as they not only shield the signals from emf etc. they also provide a ground path for the CDI box.