HELP! This is a puzzle
 

Ran on Tues - not on Wed. Nothing changed between times.

Wiring has been checked by two different knowledgeable people. The wiring is correct and connections are tight.
Timing is right on and point gap is .018. Rotor to body contacts is .025 and even at all four contacts. Plug gaps are .035.

Here's the catch - spark to the points, but not to the plugs.
Could it be the coil or the condenser - and would they fail just like that?

Remember, it ran one day, but not the next.
Any help, thoughts, or experience would be greatly appreciated.

Thanks,
Tom

Re: HELP! This is a puzzle
 

check coil, condenser, rotor, coil wire and cap, your losing spark some where in one of those, change one thing at a time till you find the problem

Re: HELP! This is a puzzle
 

If the spark is erratic, could be a possible ignition key switch problem.

Re: HELP! This is a puzzle
 

Coil-Remove high tension wire from the distributor.With the key on turn over the engine,with the lead held close to the block a spark should occur. If not the problem is in the coil or the wiring to the coil. Or Condenser check remove the cover and cap of the distributor-with the key on place a screwdriver between the points-If you have spark, fine, but if not you have problems with condenser or wires leading to the distributor. If no spark to the plug straps-Problem is in the distributor back.

Re: HELP! This is a puzzle
 

If you have the correct stranded wire coil wire, and not the modern carbon wire, that should be good.

I've seen rotors short to ground (distributor shaft) on a few cars.

Re: HELP! This is a puzzle
 

My 29 PU did the same thing. It ran nice. I went in for an hour or so, came back out, wouldn't start or spark at all. I replaced the coil wire to the distributor and it ran every time. The one that was on it just went south, and I thought I had ran it out of gas when it stalled. Everything breaks or quits working "all of a sudden". Just sayin...

Re: HELP! This is a puzzle
 

Stop the engine with the points open, then turn the key on and short the points off and on with a screwdriver blade. When you do this hold the coil wire 1/4" from a head nut. Do you still have no spark? Is so I'd check the coil or condenser.

You said you have spark at the points, so I assume you have 6 volts at the open movable points contact, plus the distributor has a good ground.

Re: HELP! This is a puzzle
 

Thanks for the responses and the suggestions. You've confirmed my own suspicions and added a couple of new thoughts as well.
I'm going out to the shop this afternoon and will report back on with the results.

Tom

Re: HELP! This is a puzzle
 

Is rotor contacting the cap?? Is the dist body good??
Paul in CT

Re: HELP! This is a puzzle - Solution!
 

First of all - Thank you all for the help.

The solution turned out to be the coil. Just replacing it with a new one got things running again. I would have thought it would be a gradual failure resulting in a weakening spark that would be indicated by declining performance.
Also, in thinking about it, I don't recall even hearing about a coil failing before.

Anyway, in addition to the replacement, I'm going to check on some of the other suggestions brought up just to keep everything shipshape.

Thanks again,
Tom

Re: HELP! This is a puzzle
 

I also had a coil that would just quit when ingot the "urge" to. An hour later it worked fine. I finally figured out what was happening. End result, coil in trash can, car runs better than ever. I didn't realize that coils sometimes just go fluky. :rolleyes:

Re: HELP! This is a puzzle
 

Thanks for getting back with the final piece of the puzzle!! Enjoy and drive the A !!

Re: HELP! This is a puzzle
 

tom, what was history of the coil? Was it in the car for a long time?
Bob

Re: HELP! This is a puzzle
 

It had been in the car a long time, never a problem. Then the car had to sit for about a year, inside, covered. After the usual minor attentions - new oil, gas, water, battery charge - it fired right up. All was well for about a week, then not. That brings us up to this week.
Tom

Re: HELP! This is a puzzle
 

Did you maybe have a short in the wiring somewhere that caused the coil to heat up and "burn" out? Might want to check the new coil to see if it is warm. If so you may have a short somewhere.

Re: HELP! This is a puzzle
 

May be worthwhile, if you check out the wiring to take off the ground cable and make good contact with the frame again. I have an auxilary ground from the center frame , at the ground over to the transmission. I run an alternator and 12volts, and a ground is important. I have been on tour and got a car running again by cleaning up the ground. By the way, diet coke is a good hand cleaner.
Bob

Re: HELP! This is a puzzle
 

Probably an oil filled coil that had leaked some of the cooling oil or the upper windings overheated and burned out because the coil was mounted in the normal model A fashion with the wire connections at the bottom . Oil filled coils are normally or should be mounted with the tower and wire connections pointing upward. I either run original solid tar filled or performance epoxy filled coils on my model A's. Oil filled coils don't usually hold up all that long when used on model A's , mounted in the normal model A way .

Re: HELP! This is a puzzle