Ignition Wiring Issues/No Start

[zmayne]

Hey Guys,
My '69 911 is getting close to being back on the road after a five or year six hiatus in storage.

I seem to have screwed up the coil/ignition wiring thanks to a lack of good notes from when I took the motor out for detailing. The engine is a '73 2.4T. It does not have a CDI in the engine bay (and never had one). I recall my mechanic a few years ago bi-passing an aftermarket electronic ignition box.

I have a green wire from the positive side of the coil going straight into the distributor, a black wire (tach, I'm assuming) going from the negative side of the coil to a wiring harness at the back of the engine bay. There is a large light green wire that goes from the negative side of the coil to a three-prong plastic outlet near the fuse bracket on the driver's side of the engine bay. This has a red wire on one end that disappears into the wiring harness and on the end with the light green there are two red wires spliced together. One of the red wires goes into a larger wiring harness and the other one goes to what looks like a condenser mounted on the fuse bracket.

I figured this was a shot in the dark since diagnosing wiring issues with a photo can be near impossible, but figured I'd see if anyone here sees anything obviously amiss.
Also, is there an simple way to rewire everything just to get the car started? I have fuel, but there is no spark when I turn over the motor. And yes, I know the wiring is a mess.
Thanks!

Here are some photos:

[Porboynz]

I'll have a go at helping, if you want to get her started without the CDI it is possible. You need to make sure that you have a ignition switched positive voltage wire going to the positive terminal of the coil. The negative should go from the coil to the points. You must have a capacitor across the points, any aftermarket ignition points capacitor can be fitted. There is a mounting screw on the side of the distributor you can attach the capacitor to, the wire goes to the points. It looks like you have a regular 12V ignition coil, make sure its not the CDI coil as they are different and make sure its not a coil designed for a resistive feed or it will over heat with a permanent 12V. With power to the coil you should be able to create a spark now by using a screwdriver to manually open the points, the spark is created when the points open causing the magnetic field to collapse in the coil. (Connect the coil centre terminal to a spark plug laying on the engine case for this test.) Once you have a spark, reconnect the coil and distributor cap and ignition leads correctly and time the engine in the normal way and engine should start all things being present like fuel and compression. When I first got my 911 the CDI unit was sitting in a box and the previous owner had the setup I have just described. Strange really because the CDI proved to be in working order, in fact still in use 15 years later. By the way, I think there is a Black purple wire that feeds the tacho from the points. Looking at your photos, I can not see an ignition points capacitor on the green wire from your coil to the points, you need one!

[James Brown]

try this, and clean up them wires, how can you figure anything out??

[Porboynz]

A picture is worth a 1000 words. You can see how a full 12V is fed to the coil while the engine is cranking and then its fed 12V via the resistor when you release the key to return to the run position, that's the resistor type coil. FYI capacitor = condenser, you need a .25 microfarad condenser or thereabouts to prevent the back emf from frying the points.

[ddinham]

Zach,
If you would like, I could come by some time and have a look?

Dana

[zmayne]

Thanks for all the help guys. Still poking away at it.

Dana, that would be great if you'd like to come by. I live in Nob Hill, near Carlisle and Central. What part of town are you in? I'm going over to Flagstaff/Sedona for a few days this week, but will be back by Thursday.

[ddinham]

I will send you a PM.