Here's a picture of my Bosche coil. Stock 1971 w/ FI.
Was running great then engine cut off. I pulled open lid to see black smoke coming from insulation around the wire leading to the negative terminal of the coil (I think). I can't tell which wire this is. It has black insulation with a red strip. It's the wire running to the right side of the coil in this photo underneath the black wire w/ red connector in the photo.
You can see the exposed copper where the insulation burned away.



This burned, exposed copper wire runs into a larger diameter insulator with other wires back to the relay on left side of engine compartment. You can see it melted the rubber insulation all the way back to about 12" short of the relay board. Do i need to replace this wiring harness?

I pulled the cable from the center of the distributor and checked for a spark against the fan housing but nothing. Engine turns over but obviously doesn't start.

I'm assuming my coil just went bad? Could this be a symptom of a bigger problem?
Thanks in advance

If it was stock points you hooked it up backwards.
If not you shorted out somewhere.

You may have a short,
The worst I would think maybe burnt point or/ and condenser.

Thanks guys!
I was driving while this happened so it was hooked up correctly. Perhaps the red and black wire in the picture is backwards now?

Anyway do you guys suggest just hooking up a new coil and trying it?
Because the + wire from the relay is what burned up I'm thinking no power got to the points so they are fine.
Is the condensor the small box above the coil in the picture?

Hi - the condenser should be a small cylinder sized object (say half the size of your thumb) connected to the side of your distributor. I saw the black box/connector that you referenced but I don't know what that is. I too have a 71 in my garage, I will go take a peek and see if I have something similar.

Reg

I don't see a small box above the coil , but the condenser is attached to the side of the distributor . I would hook it up correctly, check the points, cleanup / replace burnt wire. And most importantly, look for the source of the short, ie exposed wires , then give it a try.

Attached picture has an arrow on the condenser. Good luck.

Okay,

Thanks for the great info everyone
I tested the voltage of the red/black wire running to the coil from the relay. It's 12V w/ ignition on. This leads me to believe the problem is the coil is burned out as it's getting power but not transmitting it to the dizzy.

Does my thinking sound reasonable?

Clearly not...
I tried a new coil. Still doesn't start.
What else could have been damaged?

Are you sure the points are ok inside the dizzy ?

What "relay"? There is no relay in the ignition circuit.

Point/condenser (green) wire to the (-) side of the coil, along with the tach wire (thin black wire with a purple tracer. Power wire from the engine relay board to the (+) side of the coil. Looks to me as if the tach wire goes to the (+) side of the coil. BBQ time ...............

The Cap'n

Thanks for the info guys. Does this picture help? Positive lead is the bottom one in this picture. power from relay board is not hooked up in this picture. It is attached to the upper (negative) lead when it is.




I've doubled checked the haynes manual. They don't mention the external resistor you can see hanging about 10 o'oclock position on the coil. This resistor is mounted to the same terminus as the lead from the relay box. Is the coil supposed to be grounded to something other than the points? It seems the "resistor" is grounded to the engine casing.

Anyway, Pelican parts states:

Thick black or black/red: (+) terminal
Green points/condensor wire: (-) terminal
Black/purple wire: (-) terminal

Only three wires. Like the Cap'nsaid. Large black to +, small black with purple
(It just looks red), and the green (or black) from the condenser
to the - . I too see the tach wire on the wrong side. That resistor does not belong there.

The coil can totate in the mount and short out against the tin causing a, well... FIRE!

"15" is (+). That's where the 12v positive wire from the ignition switch goes. "1" is (-). That's where both the point wire and the tach wire go. That other device is a capacitor meant to reduce ignition "noise", and it's also on the wrong side. Eliminate that, as in "throw it away". Because I don't see a green wire in the picture, I can't identify what your wires are. Let's have more information there. BTW, look at the points and the wire inside the distributoe and make sure they're OK. Might be a good idea to leave the tach wire off until you identify the problem and fix it. The red and black wires in the picture look suspiciously like Pertronix wiring .........................

The Cap'n

I think that's what happened here!!!!! So, if that happens, and the 12V power supply from the relay board catches it's insulation on fire...what just broke? I'm no longer convinced this is a coil problem

As the Cap'n suggested, I think I have an electronic ignition. No condensor and I definitely have 4 wires...
I matched your suggestions for correctly wiring the coil, no change

If I'm not getting a spark from the coil and assuming everything is wired correctly, any other thoughts on potentially damaged components?

You will have to chase the wiring back and see how much of it is fried. Splice in new. Hook up everything correctly. Then try to start it...

I spoke with George at AA. He recommends pulling the electronic ignition out and replacing with a points system as I likely burned up the pertronix unit.

I'm going to pull the wiring harness for the ignition system and replace the wire that fried its insulation and double check that there are no other exposed wires.
He mentioned it could be the tach that burned up as well and I haven't tried starting it without the tach attached to the coil. I will check that first to rule it out

I will install the points w/ a 0016" gap to start as I don't have a dwell meter. I guess it's time I picked one up.
I hate to be elbows deep this fast in the game! Day three of ownership

The tach wire is the back/purple one. It looks fine in your pictures. I'm surprised it would run, but you had the power wire (which burned) hooked to the wrong side of the pertronix. You need to replace that wire, get a new Pertronix, and hook it all up correctly.

for those in the tri-state area...Pete in now the owner of Tim's '71
and those of us that drove with Tim know this car performed greatly.

hopefully Pete gets the wiring back together properly and doesn't fry much more of the system.....

.....just slap some points in there and drive the darn thing. If you mention or PM me your location, I could assist you with a dwell meter.

Ray thanks for the help via phone.
I'm in Richmond VA if there are any experienced 'teeners reading this I would love someone to oversee my fiddling. PM me please...

After talking with with Ray and George, and everyone's very helpful info on this thread I'm going to open up the dizzy and do just that, back to good ol' points and the original bosch coil.
I'll report back...

Make sure to get a Bosch condenser too.

The Bosch blue coil is slightly smaller than what used to be stock for the 914. You will have to add additional padding under the clamp to prevent the coil from rotating.

Same thing happened to me too when i had my 2056 ...

I wrapped mine in bicycle tire tube...

Pertronix failure...hopefully it's the only thing that is broken. Fingers crossed.
Won't have points to put in until Wed or Thurs...

Points and condensor in. Dwell set to 48 and she's running! I'm using the original coil too, it had nothing to do with it.

My issue now is the timing. I have it running great but I can't get the dizzy retarded enough to make 27 BTDC (or at least where PP says it should be). I see no marks on the housing of the fan.
I have it set now to the left side of the large fan support, rather than one blade to the right as suggested on this site and others for the 1.7 fan. It seems to idle and run through the RPM range best here after multiple drive tests with adjustments.
Why would this be?
It's running really nicely with no weird tendencies but I'm weirded out. I don't want to burn up my valves, etc...

Your plug wires could be one tower off, or the distributor drive gear could be one tooth off causing the diz needing to be out of position to get enough advance to run. Can you shoot a pic straight down on the diz and back out far enough for the oil fill tower to show up too?

The Capn' is right.
And I now see I am late in the game, but...

To clear things up, you do not have to ground the coil case. I thought so for a long time but both windings have a common ground which is connected and disconnected by the points or electronic gizmo. Such as Pertronix. I have enjoyed Pertronix units in several cars and the Capn' is making me pack a spare dizzy now. Thanks for making me nervous Capn' .

The tach wire goes to the ground, i.e. negative side. It reads the fluctuating voltage and turns that into RPM. I hope your tach works. Now that I see what is wrong it ought to.

It looks like pertronix to me too. I was wondering about where the power was coming from - it should be hooked to the side with the red lead. Now I get it, the #15, ignition +12V lead is hooked up to the wrong side of the coil to the black lead. I cannot see the trace, but it isn't the purple one. I cannot figure out why it ran at all.

Just something to store away for later. The coil in these cars serves two purposes. One of them is as a transformer upping the primary voltage to a higher secondary voltage. The second one is an energy cell, so that when the primary is suddenly disconnected the primary voltage spikes from electromagnetic momentum. That gives a higher voltage to amplify. Equivalent to water hammer when you suddenly shut off hundreds of pounds of flowing water at the sink.

Modern units like MSD use a different mechanism to give a high spike in the primary, but the old points method is pretty sweet for its day.

For the padding, a multi-layer application of duct tape works just fine. Wrap it a bit thick, unwrap layers until you have a snug fit. Trial and error, here.

The Cap'n

This just happened to me and it was the AAR shorting out.

I don't know if your car has one or not, but if it shorts out (common from what I'm told) that can be your source of the fault.

If you have the AAR, there is a +12 wire going to it. Maybe if fell off or the valve shorted inside. (that was my situation).

Good luck!

Len

IIRC, there is at least one good article in the archives detailing the procedure for setting the timing. If you can't find it, or if it doesn't exist, lemme know and I'll do one. BTW, I just wrote one somewhere near the top of the front page of the Garage forum in the last couple of days.

The Cap'n