No Power from Coil to Distributor?!!!

[TheWhiteElephant]

Okay, so I replaced starter, cap, rotor, points, coil, plugs, wires on my 1973 K20 350 points ignition. It ran before I did all this, and now it won't start. I've done a fair amount of research but haven't found an answer. Here is what I've done so far:

1) Engine cranks great. Battery is low but I hooked it up to a charger w/a quick start so I'm getting a good, healthy crank.

2) Yellow wire from starter 'R' to (+) on ignition coil

3) Black wire from distributor to (-) on coil and the external condensor to (-) as well.

4) I am getting no spark. I tested the coil at Autozone, resistance is within specs.

5) I put the key in the 'on' position to check for power from the switch to the coil. I attached the voltage tester on the (+) side of the coil, grounded it to the manifold, it lights up to 12V, meaning I'm getting power to it.

6) I disconnected the coil-to-distributor wire and had my wife (haha) crank the engine and put the distributor end of the wire close to the firewall, then brake booster to check for spark, but nothing.

As far as I can tell, this means I am not getting power from the coil to the distributor. Anyone have any idea what is going on? I'm stumped on this. For whatever it is worth, I'm getting a healthy dose of fuel to the carb, but no spark.

Any advice would be greatly appreciated. I'm seeing the light at the end of the tunnel for this first stage of the build up, but this is a big bump so far.

[Restrorob]

Put one voltage tester lead to the negative post on the coil (going to dist.) and the other test lead to a good ground, Watch for a pulsing voltage while cranking the engine over.

If you get no pulse in voltage check the wire going from the coil to the points for any shorts (going through the dist. housing) or for any internal breaks in the wire, Also make sure the wire connector didn't spin when you tightened it on the points screw and is now touching the mount plate.

Make sure the points are adjusted to .019" or 30 degrees dwell and the contacts are clean, Use the edge of a business card with a shot of carb & choke spray cleaner (NO GUNK BRAND) or rubbing alcohol to clean the point contacts.

Is this uni-points (points & condenser together) you installed or separate points and condenser ?

[TheWhiteElephant]

Originally Posted by Restrorob

Put one voltage tester lead to the negative post on the coil (going to dist.) and the other test lead to a good ground, Watch for a pulsing voltage while cranking the engine over.


Is this uni-points (points & condenser together) you installed or separate points and condenser ?

Thanks for the suggestions. I tested the negative coil post in the key "on" position but not while cranking. My voltage tester only has a light, but I'll give that a shot.

Yes, it originally came with the uni-points so I replaced those with a new set. I have not yet adjusted the points. It is actually impossible to gap them with the uni-points because there is no way to stick ANYTHING in there because the condenser is in the way. I'm guessing the only way to adjust these is with a dwell meter? Still, with no power to the distributor, I guess that is point-less (excuse the pun) at this point.

I "forgot" to test power at the coil while the key is in the crank position. Will do that and update the post.

Thanks again for the suggestions. Anyone else?

For what it's worth, with what I spent on the cap, rotor, points, condenser and coil, I spent more money than if I would have just bought a new Summit HEI distributor!!! If all else fails, I will toss the points distributor and buy the Summit HEI as it was in the plans anyway. I don't want to wanna be messing with the points, anyway.

[TheWhiteElephant]

By the way, I have only checked power to the coil while the key is in the "on" position. Am I supposed to perform the same test while cranking the engine?

[Restrorob]

Originally Posted by TheWhiteElephant

Am I supposed to perform the same test while cranking the engine?

Yes, On the neg. side (going to dist.) while cranking. This will tell you if the points are opening and closing or if the contacts are dirty (oil from fingers installing them).

I test light works best for this test, I just couldn't tell from your post what you were using. The points are the ground point for the system, As they close they ground. This is why you will have a pulse in power while cranking which will tell you if there's a problem with the lead wire or points if there's no pulse.

I've never had any issues getting a feeler gauge in the points for setting, Cap and rotor off and you should have room.

[TheWhiteElephant]

Originally Posted by Restrorob

Yes, On the neg. side (going to dist.) while cranking. This will tell you if the points are opening and closing or if the contacts are dirty (oil from fingers installing them).

I test light works best for this test, I just couldn't tell from your post what you were using. The points are the ground point for the system, As they close they ground. This is why you will have a pulse in power while cranking which will tell you if there's a problem with the lead wire or points if there's no pulse.

I've never had any issues getting a feeler gauge in the points for setting, Cap and rotor off and you should have room.

Thanks for the input, Rob. I'll give it a shot because with all the info I've gathered, everything seems to be "pointing" to the points. I didn't realize if the points didn't open/close there would be no power going into the distributor to complete the circuit. I will give this thing a go and post my results. I appreciate your advice.

[72lb4x4]

The switching action of the points is what generates the high voltage to make the spark. A bad condenser/capacitor allows the points to burn from the arcing across them. A bad condenser may cause a weak or no spark as well, but start w/ the point gap/dwell.

[allengator]

Originally Posted by 72lb4x4

The switching action of the points is what generates the high voltage to make the spark. A bad condenser/capacitor allows the points to burn from the arcing across them. A bad condenser may cause a weak or no spark as well, but start w/ the point gap/dwell.

AGREED.... The points are "closed" so you get 12v at the primary side of the coil... But it takes the "opening" of the points to cause the magnetic field to collapse on primary side to induce the high voltage SPARK on the secondary...

Place a 12v test light across the the coil and crank the engine.
The test light should go on and off as the points open and close.

My bet is that it will stay on because the points aren't opening.
An alignment of the points should fix the problem.
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[TheWhiteElephant]

Guys, thanks so much for all your responses. I went back and adjusted the points with a business card and bingo! Truck started right up. Unbelievable. To be honest, out of all the other times I've ever installed points, I've never adjusted them and the cars have run fine, so I just took it for granted. Live and learn Thanks again.

[allengator]

Glad to hear it!!!
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[Restrorob]

Originally Posted by TheWhiteElephant

I went back and adjusted the points with a business card

The average business card is only 0.10", For peak operation they need to be opened up to .019/0.20" or 30 dwell..... Least it runs now !

[LONGHAIR]

Originally Posted by TheWhiteElephant

To be honest, out of all the other times I've ever installed points, I've never adjusted them and the cars have run fine, so I just took it for granted.

You have been extremely lucky that they even ran.... and leaving performance and fuel economy on the table.

[TheWhiteElephant]

Originally Posted by LONGHAIR

You have been extremely lucky that they even ran.... and leaving performance and fuel economy on the table.

haha! I was thinking the same thing.

[allengator]

Originally Posted by LONGHAIR

You have been extremely lucky that they even ran.... and leaving performance and fuel economy on the table.

ok... I agree with the second part... But "extremely lucky that they even ran"?????
No... EVERY set I have ever installed (dozens) would start and run as long as they were switching on and off... I have always started the car after install and before adjustment...
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