Electrischer Schaltplan 1970 ignition?

[jp02ti]

So, I am tracing several issues.

1. stumble in ignition, which may potentially be related to electrics?

2. in-operable headlights, both low and high beam.

Initially, I found that this car had an ignition relay and ballast resistor fitted, despite being a 1970 6 fuse car. naturally, i removed both. the wiring now matches the Elktrischer Schaltplan for the early 6 fuse 12 volt cars. this is good. I have the Bosch blue coil, so removal of the ballast resistor is ok.

I traced the wire from the coil back to the ignition switch, and it looks ok, there were no obvious breaks or cracks. from the ignition, I traced several heavy red wires, one heading towards the battery, one heading towards the light switch. the light switch itself is in good condition, but upon checking the dimmer switch I saw the attached. posts 56 and 56b are melted. the wires themselves look ok, but the housing is clearly in bad shape. I have not attempted to dismantle the switch itself to determine the condition of the internals. I’d like to find my heating iron before I do that to soften the sides while I open it up.

I see no damage to the wires between the switch and the dimmer, but obviously something is wrong.

So, is it possible that there is a connection between the ignition and the lights? The lights are clearly non-operative. Could it be that this issue is feeding backwards up into the ignition system through the ignition switch post 30?

The other clue to this whole mess is that the tachometer will bounce slightly. I know the coil is good, and the wire from the coil to the tach has been completely replaced. The old wiring may still be present, I need to check for it. If the old wiring is present, and is grounding, this may be feeding back into the coil and causing the stumble?

I am REALLY not enjoying this anymore. This stumble has been around for 6 months now, and I’ve replaced damn near everything in the whole fuel-air ignition system.

New plugs, points, coil, condenser, wires, distributor, fuel pump, fuel filter, cleaned out tank, flushed lines, cleaned out carb bowls, cleaned out carb screens, timing set with light, dwell set with meter. Ran without exhaust for a bit in case it was choking it. I have 14 volts when driving, and the voltmeter is steady.

I’m open to ideas, thoughts, ruminations, opinions, and yes, perhaps a bit of ridicule. How can such a simple car have such problem.

Thanks,

Jon

[allbim]

Bypass all components you don't trust and feed 12V directly to the coil.

If that makes a difference take it from there.

[aa/fd]

I agree with allbim and would supply the ignition with an isolated power source, separate on off switch less tach connection and give it a test run.

If OK add the tach back in to the circuit, if OK then look at the ignition switch as culprit. To me the bouncing tach is a big clue, they only go to zero when the power is interrupted. The dimmer looks like it might have hosted higher wattage lamps for a time in it's service life. Or maybe they just look like that when they are cycled out.

[jp02ti]

yes, actually, the headlamps are no longer sealed beams, they were upgraded to euro H4s. Looks like I'll need to add in relays and fuses on those lines. its one of theose projects which was in line but on hold while the ignition issue was resolved. only upon further exploration did I suspect there may be a link somewhere.

good advice, thanks!

Jon