Ballast resistor wiring

[Mattax]

So in my photo would you be saying that J2B and J3 are joined in the connector and still effectively running from the ignition switch to the coil and are still an active part of the start ignition circuit, with power coming from J1 via either R6 or A1A?

I don't think the original J3 is providing power to the ignition during start because somehow the ECU needs to get power.

Yes A1A provides power battery power during start.
Then R6 provides the power when the engine is running.

And then J2 / J2a (as its a 69 model) is bringing power to the 4 pin resistor and feeding the coil via the red wire labelled coil in my photo?

That what it looks like to me as well. The top resistor should 0.5 ohms

Looking at the coil it has 2 wires in to positive - the pinkish wire from the 4 pin resistor that I labelled Coil and another red wire, perhaps this is a continuation of J2B / J3? It's my only explaination, they disappear into a mess ofwires in electrical tape and the red wire comes out of it further along.

That is odd.

The black and yellow wire to the negative on the coil I think does run to the top pin on the ECU as shown in your diagram, there is a second wire (red) from the negative on the coil which I believe might have been to an aftermarket tachometer.

That would make sense.

 

[Righty]

Definitely need to unwrap these wires, it's the only way to see whats been done.

 

[Mattax]

Lets move stuff around on the diagram. As built in 1969

If the ECU is newer than late 1970s, this would be functional as the 5th wire is not needed due to revised internals.

But yours is set up for original ECU design. I'll stick with the typical colors but the important thing is the position on the pentagon shaped plug.

Maybe its something like this

 

[Mattax]

At least on paper, this would have been the simplest and cleanest.

There's a chance that the voltage regulator has been changed to a solid state unit. This was frequently done when converting the ignition to electronic. It could be the same type as original (regulator controls feed to alternator's rotor) or may have been switched to the ground controlling regulator (has a triangular plug on regulaor).

Anyway. Your current problem is the ignition cutting out sounds like its related to things moving, so look for a poor connection in the ignition circuits.

 

[Righty]

At least on papThere's a chance that the voltage regulator has been changed to a solid state unit. This was frequently done when converting the ignition to electronic. It could be the same type as original (regulator controls feed to alternator's rotor) or may have been switched to the ground controlling regulator (has a triangular plug on regulaor).

Anyway. Your current problem is the ignition cutting out sounds like its related to things moving, so look for a poor connection in the ignition circuits.

This makes sense to me - so tallying this up with our mystery red wires:

1. Second red wire to + coil: Either J2B leaving the old resistor turns into this second red wire at coil positive or J2B and J3 have just been cut off and left attached to the old resistor and have been replaced by this red wire running from the ignition switch.

2. Mystery additional red wire with white stripe attached to the 5ohm side of the resistor where the green wire (on your diagram) comes in from the ECU: My only thought is could this be a feed from say the battery or starter relay to provide battery power to the ECU at start when the alternator is not providing current?

 

[Swinger 340]

Yes I have the 69 diagram, so I had been trying to translate that to how the ECM was incorporated.
So in my photo would you be saying that J2B and J3 are joined in the connector and still effectively running from the ignition switch to the coil and are still an active part of the start ignition circuit, with power coming from J1 via either R6 or A1A?
And then J2 / J2a (as its a 69 model) is bringing power to the 4 pin resistor and feeding the coil via the red wire labelled coil in my photo? The pale blue wire from the ECM in your illustration corresponds to my dotted yellow wire connecting to J2 but what do you think is the reason for the dotted green wire and also the red wire I marked with a question mark?
Looking at the coil it has 2 wires in to positive - the pinkish wire from the 4 pin resistor that I labelled Coil and another red wire, perhaps this is a continuation of J2B / J3? It's my only explaination, they disappear into a mess ofwires in electrical tape and the red wire comes out of it further along.
The black and yellow wire to the negative on the coil I think does run to the top pin on the ECU as shown in your diagram, there is a second wire (red) from the negative on the coil which I believe might have been to an aftermarket tachometer.

Just saw your little arrow and ? on my photo next to the yellow and black wire, I think this is the wire that goes from the top pin on the ECM cap and runs to the negative on the coil.
.View attachment 1716414073

You are using an Accel Super coil. They need a 2nd ballast that comes in the kit. I have one on my 340 for over 40 years and never had a problem. Get ahold of them for a replacement, if you don't have one.

 

[Righty]

You are using an Accel Super coil. They need a 2nd ballast that comes in the kit. I have one on my 340 for over 40 years and never had a problem. Get ahold of them for a replacement, if you don't have one.

Thats interesting, just lookes up that coil and like you say they have a 2nd resistor in series with the OE resistor. I have not seen it when I was looking before, but then again i wasnt expecting to see one. I need to take a look and see. Thanks.