If it were me I would be pulling that solenoid off the starter and checking it out.
Like testing it on the bench.

 

I did take the solenoid apart while I had the starter off. I disassembled the starter solenoid and everything looked correct inside. Should the two wires that go to the starter have an increase in voltage when the key goes from on to the start position?

 

Yes.
The huge center 0 ga wire has 12v all the time.
The "S" or (Start) 12 ga wire gets 12V from the ignition switch, but only when the key is held in "start"
The "R" or (Distributor) stud goes hot from within the solenoid, and only when the other "S" stud has 12V applied. It sends 12V thru the 20 ga yellow wire, to the coil +.

That "R" stud, with the wire removed, but the other two wires attached, should only show volts when both of the others are fed with 12V, and you hear the solenoid click.

 

Thanks, I’ll start with these items and see where it goes. To clarify, is the 12 volts dropped from the (R) terminal dropped via a resistance wire before going to the terminal?

 

the wire from the R terminal gets 12v when the solenoid is engaged by the S terminal . That feeds 12v to the coil while starting . If the wire from the R terminal is disconnected from the coil there should be no voltage on that wire from the starter except when cranking (at the coil) . If the 2 wires are connected at the coil you should see the same voltage at the coil and the R terminal . Try just connect the resistor wire from the fusebox to the coil and ignore the other wire . The engine will still usually start it may just be hard starting . You could also run a jumper to the + side of the coil from another source to make it start easier . The jumper is just doing what the R terminal on the starter does

 

This video explains it better than I could in a thousand lines of text.

The ballast resistor doesn't "drop" the voltage. It acts as half of a voltage divider circuit, when current flows through the coil (when the points are closed). The coil and the ballast resistor have a similar resistance, so you should see about half of the battery voltage when measured at the appropriate time (points closed) and place (on the coil + terminal, while connected).

 

Electricity has baffled many of us over the years.
Now that is an excellent video!
What it shows clearly is that the resistance wire from the ignition to the coil, will show 12V when NO current is flowing, like when the points are open.
And then when the points close, and the current flows to thru coil, it will drop to 7V or so.

You could actually test that by slowly opening & closing the points, firing a spark plug., and measuring the voltage at coil pos. You don't even have to run it. I do not know if a multi-meter could read the 2 voltages fast enough while running, I'll bet it just averages them. The cycle is too fast.

Since it runs pretty good, most of the time, I'll guess the ignition is fine. But trust and verify.

If it passes that test, I would find a chassis dyno to run it while you can test the AFRs. They might have been ok on the dyno, with open exhaust, but with the cam overlap (10" vac at idle right), and factory stock mufflers, it could cause serious leaning out of the mixture. It might be lean as *** now. And that makes it burn your eyes. And it will mis-fire if it is too lean, and ~2600 or so is usually the leanest spot. Jebbysan suggested this ages ago, and it got skipped. Duntov himself mentioned the stock mufflers choke 50HP out of a BB. And if it is lean, it would be even worse. I have seen many cars that needed re-jetted after changing the mufflers.

Does that describe all your symptoms?

 

I got a bit of time time so I untaped the wiring loom that goes down to the starter for inspection. Several questions, does the purple wire that transitions to red with a cloth wrap look original? The crimp connection does look factory to me. Second, the lighter gauge cloth wrapped wire (run wire) has several questionable areas that I patched. If it’s stock length is there an ohm ready that I can measure?
If it’s damage is there a direct replacement for this wire? Not sure how to replace a resistance wire?
Thanks, KC

 

I have only seen the purple wire with no splices go to the starter . That looks like someone "fixed" the wire and used a wrapped wire for heat protection . Same goes for the cloth wrapped wire for the R wire . I would be suspicious of the thin wire . I only ever remember the cloth wrapped wire being the factory resistor wire .

 

I am glad you pulled the wires.
Do you have a multi-meter? Reads Ohms and volts?
If not time to get one.
You mentioned you want electrical help.

• Blue arrow / loose wire with 2 lugs. This must be the start "R" wire to coil "+". It should have zero resistance. Use the low 1-10 ohm scale. Better read Zero. If it has bad connections, replace it. They look shaky. This should not be a resistance wire. Test it with no battery, not hooked up, just your ohm-meter. 20Y in diagram below.
• Red arrow / bigger wire with bigger lug. 12R in diagram. Goes to starter B terminal. Supplies power to the entire car. Green arrows are the factory crimps where the factory fusible link is, that link is brown wire between the crimps. 14BRN in diagram. Turns into 10R (red) after fusible link. Goes to horn relay and alternator. Find a 10R (red) at those 2 locations, and with no battery connected, check with your ohm-meter. All 10R wires should connect.
• Yellow arrow - 12PPL in diagram. Should look faded red / purple somewhere. S terminal on starter. Should have a crimp/splice joint somewhere and stays 12ppl. Goes thru fuse block. Goes to both clutch safety switch and main ignition switch on bottom of steering column. 12PPL there too. Should only go hot when you turn the key to start, but you do not want to test it that way. Test both ends with ohm-meter starter end and clutch pedal switch end. Should be zero ohms. Not a resistance wire. You may need another 6 foot jumper wire to help test it.
• Black arrow - Mystery wire! From the starter!?!? am not quite sure what this one is. It should not have come from the starter, there should not be any more there. It is a small dia and black wire. If this goes to the starter you found your weird hookup.
• Two more wires need to be traced / tested:
• The distributor points wire. That is a very small dia wire. Probably black. Only goes from the bottom of the distrib to the coil (-). The distrib wire should be the only wire on coil neg. It should have no resistance on your ohm-meter. Test from points to end of wire. It is possible? that this is your Black arrow wire above? But it should not go to the starter!
• The 2nd coil pos wire, we need to still find and test. This is the resistance wire. On the diagram the resistance wire is marked 20W-R/B. White with R/B stripes. It goes from coil + to the fuse block. It pops out on the other side of the fuse block and connects to 12ppl under the dash. So that is how you can test it. From coil pos end to 12 ppl almost anywhere. Ohms scale. But this time it should read somewhere around 2 ohms. This is the only wire that should give you an ohm reading.

Remember this diagram has the coil + and - backwards!!!


Complete wiring diagram, save to desktop, open and zoom in.

 

Leigh, thanks for the diagram and notes. The black “mystery wire” with the round terminal was grounded at the starter mounting bolt or to the engine block.
Im going to start testing these when I get time, may take a bit but I’ll report in.
KC

 

Not sure what that mystery wire is.
The starter and engine and alternator and everything on the car's engine grounds thru the main block to frame ground wire. It is huge. Battery cable size. Under the pass side engine mount, block to frame.

Sometimes it gets corroded, removed or forgotten, oops. Lots of weird issues then.

 

The black wire with the large eyelet is the upper firewall ground wire. If you trace it up you'll find it grounds the blower motor, wiper motor, TCS sol, and hood alarm switch (if so optioned).

 

Leigh, I checked continuity from the black arrow wire (round end) to the small black wire that was attached to the (P) side of the coil and found continuity thru them. I’m thinking this is very incorrect and surprised the car would even run as the large round end was grounded at the starter attach point. I basically had a positive on one end and a negative on the other end?

This car was VERY untouched so the big question now is what is going on with the black arrow wire that is down by the starter? That and replacing the small wire from (R) starter to (P) on the coil.
KC

 

Yes it sounds something is wrong. It may just be some wire is attached to the wrong screw. Or not.

Hammerhead Fred sounds the black arrow mystery wire is a ground wire that should trace to some components on the firewall.
All grounds should basically connect.
But it should not be connected to the coil Pos, of that I am sure.
Who knows what kind of voltage feedback that would cause.

I would go back to my earlier post, and also trace both wires on the coil, to make sure everything is OK.
Take a pic, and let us know what you find.

 

My '67 uses the black ground wire to the outboard starter mounting bolt - like Hammerhead Fred said. It definitely does not go to the coil.

Is your harness taped like factory or is other stuff spliced and jerry rigged? You might want to consider installing a new engine harness (~$330). It serves all of the firewall electrical needs from the fuse box to the heater fan. They are simple and quick to swap.

 

Hammerhead, I missed this reply earlier. It makes sense that the black wire with the large round end is a ground but why would I get continuity thru my coil positive wire? The harness seems to be original and I’m not seeing any areas that are patched. Really lost here, but think I’m in the right area to get this intermittent miss resolved.

67.62, I did some research and fairly confident the black wire is grounded at the outboard starter mount bolt. At this point I’m guessing the wiring has been spliced because the same grounding circuit cannot also go to the coil (P) . More investigating around the wiring harness.
KC

 

My food for thought:
That does not appear to be the original starter ground bolt eyelet. The original eyelets have somewhat flat sides - so I'd begin questioning if your harness is original/unmolested.
The eyelet shown in your photo above is connected at the wrong attachment point - far easier to attach it to the starter mounting bolt - causes me to question the ability of the installer.
The original path for the Starter ground wire:The fact that your TCS relay has the original ground attachment tells me you have a grounding wire somewhere in your harness - but does it actually run to your starter?

At no point should your starter ground wire attach to your ignition system, coil or otherwise.
If you have such a wire that's a problem.

I'd question if there are two "ground" wires (original and an added one) or did someone splice into your ground wire running it to the coil.
Or did someone add a wire and cut your original wire.
Consider that the coil positive side had both a yellow and black wire attached to it.
Perhaps a previous owner mistakenly confused the black wire for the ground wire which runs just behind the coil in the harness.
The correct black wire running to the positive side of the coil should run to the bulkhead connector and into the dash harness where it is then a pink wire running directly to your ignition switch.
FYI: a poor/old/faulty/etc ignition switch (the actual switch under the column and not the key assembly) can cause intermittent ignition issues.

 

Hammerhead, I went back and looked at the black wire with the large round end. It may be hard to tell from pictures but it is flat and looks just like the other original grounding wires that ground at the outboard starter bolt. The big question now is why is the (R) wire to the coil getting continuity with the ground circuit? I’m thinking somewhere I hooked something up incorrect and just forgot about the repair or incorrect hookup. It was a nine year project so that’s a possibility.

I think the next move is to physically trace the coil wire all of the way back to the origination point? I’m going to be out for work a few days but will check back in.
Thanks, KC

 

Best pic I could locate demonstrating "flat sides". Your photo looks to have a round eyelet but somewhat difficult to tell.
Think you're on the right track back tracing the coil wire.
Keep us posted


OEM grounding eyelet