No spark- what am I missing?

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YY1

YY1

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It's been a while since I've had to troubleshoot a points system, but I did manage to get my 67 318 running a few months ago.

This time it's an unmolested 67 225 and it's kicking my ***!

The points were worn to the backing metal, so I replaced them and the condenser with new units out of the box.
Also replaced rotor.

The cap doesn't look bad, and I scraped the tower contacts with my fingernail to clear any corrosion.

I set the gap at .020 (middle of spec of .017-.023). Dwell read 8-10* on my meter.

I have 12v at the coil, and I've swapped out the coil twice, the last time from a running vehicle.

Also swapped out the coil wire twice, last time known good.

I have an adjustable gap type spark checker, and no matter what- no spark.

I could jump/replace the ballast, but if it were bad, wouldn't it start then stop when they key was released?

I thought about jumping the coil to hot, but I've got 12V there.

If I put the coil wire on the spark plug checker, should I get a spark? I got nuthin".
...and that's after three coils, the last one known good!

Seems like something is causing the distributor to fail at telling the coil to fire.


I'm about stumped.
 
Take off your cap rotate the engine to a points closed
position . Use a pencil open the points with your spark check device on the coil wire and the key on. When you open the points you should see a strong blue spark. If you don't, but have power at your points disconnect your condensor. It could be shorted.
 
^^Basically it^^ The points short the neg side of the coil to ground when closed, but the condenser (capacitor) in the distributor must be good.

Common problems........

Points defective, IE something causing a permanent short like a bad insulator

Improperly gapped

Bad "condenser"

Bad/ broken primary wire


Use a test lamp on NEG coil terminal. Rotate engine, lamp should light and "off" as engine turns and points cycle.

If tach is or other accessories hooked to coil NEG try unhooking them.
 
Hows the end play on the dizzy shaft?

My money is on a bad condensor, you will get zero spark with a bad condensor and I've had them be bad new right out of the package swap it and I bet she'll fire off
 
One other thing, crank engine while observing the rotor. Does it turn in relation to the engine? If I remember correctly, /6 use a nylon distributor gear, might've crapped the bed.
 
Coronet 500 said:
My book shows 42-47 dwell angle degrees for the six.
Click to expand...
Yes, that number is right for the dwell angle. 8-10 degrees dwell is waaaay too low, and it would not let the coil to charge right and the spark would be weak. It MIGHT be OK at idle when hot, but would crap out above idle RPM's or when the engine is cold.

Such a low dwell would indicate the gap is set waaaaay too wide. You need to make sure that the gap is set when the points rubbing block is right at the very highest part of the peak on the points cam. You can't just set the gap with the cam rotated to any position.....Reset your gap more carefully.

Also, measure your ballast resistance cold. A lot of stores will sell you one that that 1.5 to 2ohms cold and that is not right for this ignition. You need to have one that is down close to 0.5 ohms when cold. Try to find a BWD R19; I got one recently from Advance Auto. A high ballast will also starve the coil of the proper amount of charging current.

If you like, you can isolate the distributor very easily:
- Connect a jumper wire to ground and disconnect the distributor wire from coil -.
- Turn the ignition key to RUN.
- Touch the ground jumper to coil - for a moment and then disconnect; DON'T be holding the bare end of the wire when you do this!
- When you touch and disconnect this wire, you should see a spark out of the coil's spark wire every time. You are duplicating what the points do with this jumper.
(And what 'funwithfuel' says in his first post does the same thing....!)

If good spark, then its in the distributor. If no spark, and the coil is good, then the ballast is bad, or the wiring or key switch is bad. But since you have measured 12v at coil + at some point, then these are not likely the issue.

(BTW, I don't use a spark detector; I just put the end of the spark with about 1/4" from engine metal and watch it jump that gap.)
 
PeaceNGrease said:
Hows the end play on the dizzy shaft?

My money is on a bad condensor, you will get zero spark with a bad condensor and I've had them be bad new right out of the package swap it and I bet she'll fire off
Click to expand...
You can just disconnect the condensor temporarily to test to see if it is shorted; just don't run it long like that or it will burn the points.

A shorted condensor should show 0 dwell angle..... but it won't hurt to check.
 
I was looking at the wrong scale for dwell. It is 38, which is just shy of the 40-45 spec, and since the gap is .020, I think it's probably close enough.

Since the last post I've verified 12v to the points and good ground to the other side.

The condenser is brand new from the box and name brand (wells?) but it has been on my shelf for about 20 years.

I did not know it would run without that. I'll give that a try.

I also have a few more I can try, but I chose that one because it was the only one still in a box.

I also eyeballed that shaft play. Not much if any side to side but a fair amount up and down.
Checked the 67 318 and it's about the same.
 
Ok, yeah that is close enough so that it should run.

The next best step is to try the pencil test or the ground jumper test and see if there are sparks from the coil. (You can even just rotate the engine so the points are open, turn the ignition to RUN, and short the points with a screwdriver and then unshort them, and look for a spakr from the coil.) That will narrow this down to either the coil or back to the ignition switch, or inside the distributor.
 
Most points systems will not run or start with condenser removed
 
Put the wire for the condenser and coil negative wire on the insulated side of the points connection. :D
 
Oh wow. Just thought of this or remembered. Is ign2 getting hot in crank? It took me quite a while to figure that out on my ride. I could jump the solenoid, she'd fire right up. Try to start with a key, no spark. Lost a lotta hair that day. Good luck.
 
you can just drag the neg coil wire on a manifold and itll spark the coil to a wire held next to a ground. The points must be isolated from the dizzy body by their insulating washers. check continuity of the distributor wire and ground when the points are closed (cont) and open. If they are grounded then look at insulators.
 
It won't hurt to run the engine w/ 12 V to coil+ w/ a jumper wire for a short time (<2 min). Eventually, the coil will get too hot like that. That test bypasses the whole ign wiring. Also, connect your spark tester directly to the coil HV output, which bypasses the distributor's rotor & towers.

If still no spark, I would remove the distributor and spin it by hand to check things. You will need to ground the distributor's case to BATT-. If still nothing, remove coil- from the points and make your own "points" by touching a jumper wire from coil- to BATT- and releasing (mentioned in post #14). That tests the coil alone. Do not touch that coil- wire with your hand or you will feel high voltage.
 
Changed out condenser-still nothing.

I brought my remote starter switch home from the shop today.

Next I think I'll wait until dark, and see if the points themselves are sparking.

I already verified 12v into the points and good ground on the other side.

I suppose I should verify 12v while it's cranking.

I'll also try manually shorting the 12v coil lead to see if I get spark from the coil, but the coil (and wire) is off my D150, which runs.

If I get spark at the points and HV spark at the coil tower, I can then look at the cap and cap to rotor gap as maybe being the culprit.

I'll verify continuity and scuff them up a bit, maybe put the rotor on not bottomed on the shaft and let the cap pressure set it's height.

My brother's got an electronic dist, but I really hate to do a conversion on a car that was bought to cut up and that I only need to yard drive.
 
OK-

Grounded 12v lead from coil to dist with coil tower lead on spark checker.

SPARK!

Observed points with cap removed.

SPARK.


WTF?

Why isn't the 12v to ground signal getting from the dist to the coil??
 
Dist shaft spins with engine.

Points spark as shaft turns.

Coil discharges if 12v lead to dist is grounded via external jumper.

Defies logic.


I considered a poor 12v lead to dist, so I added my jumper in parallel-

No change.

I considered a bad ground path from dist plate to block/batt...

...but why would the points spark if that were the case?
 
I also removed the points, and checked them for a short.

Still, why would a spark go across the points if they were shorted?
 
what about inside the dist breaker plate? the brass contacts that can get fouled, I believe they carry the current????
 
I went through something similar last year on a gm. I put a heavy grease on the dist cam because the little pill was missing from the new set I bought and when it was cold the grease wouldn't let the points follow the cam correctly, after about a day of replacing parts I removed the grease and it fired right up ,you know how hard it is to find point lube now .
 
Oil or grease on points can keep them from making good contact. Pull a piece of clean paper through them, closed. Check resistance from ground to point lead, not connected to coil. It should read very close to zero points closed, infinity with points open.
 
A friend of mine had a break in the wire running to the points inside the distributor, resulted in a no start condition.
It was not a clean break it looked like it was ok, but no current would go thru it.
 
Here's a plan. "Gets you back to basics"

First SIMPLIFY the thing

Remove ALL wires from the coil except the distributor to coil primary wire

Use a jumper from a battery source to the coil to power for testing. Do not leave this hooked up, you can burn the points, and ruin the coil

With power hooked up, check your dwell cranking.

Bump the engine until points are closed. Power up the coil with your jumper and quickly check voltage at both sides of the coil. You should have

"same as battery" at your jumper on the coil +

and very near zero volts on the NEG terminal. If you read over 1 V those points are junk. And THAT is giving up a lot. The reading should be MUCH lower

"Assume" the coil HT lead might be bad. "Rig" a grounded wire and screwdriver probe, and while using your remote switch, hold the probe into the top of the coil, look for spark while cranking. You should get an absolute min. of nice blue 3/8" spark, and often more like 1/2" long

if you don't get a spark doing the above try....


Yet another condenser

You say? You get a "good" spark while manually shorting the points with a screwdriver? This might hint that even though you think so, the points are not really closing. I'd pull them out, inspect, and inspect the distributor for wear / shaft bearing wear. Or maybe you don't have them gapped as you think.

(Maybe the dwell meter is bonkers or you have it set wrong. Make sure you are reading the correct meter scale and have it set for 6 cylinders)

Is the distributor actually turning with the starter?
 
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