problem with dizzy on 72 240z

[jcox]

After banging my head for about a week trying to get fire from the coil I was able to get some help from this forum and finally see a flame! To make a long story short I ended up pulling the distributor from my 73 (dual points) and put it into the 72 just to see what happened. Well what happened was I had a spark from the coil.

My problem now is figuring out what the problem is with the original distributor. I need to put the test distributor back into the 73. Does anyone know of any specifics that could cause the dizzy to prevent the spark from the coil. Keep in mind I'm just trying to get the spark from the coil, I'm not concerned at this point of what happens after it gets to the dizzy. I'm just trying to see the spark from the main coil wire to the ground.

My thought is as long as the coil (-) wire to the dizzy is clean, tight etc. that would be the only thing to have any effect on the spark from the coil? I don't have a lot of experience with these things so it may just be my ignorance?

Any help is appreciated.

[Arne]

Bad distributor cap, perhaps. Make certain the cap and rotor match, too.

[jcox]

the cap would prevent spark from the coil? Just to clarify that all I want at this point is to make sure the coil is functioning properly. I'm trying to determine why it will throw a spark with one distributor (the later model with dual points) and not the one that came off of it (single contact)? I'm checking only from the HT wire from coil to chasis. My first thought was maybe a ground issue but I don't know.

[Arne]

Oh. Different issue then. Make certain that the points are properly mounted and gapped, and also that the small wire that leads from the points to the terminal on the outside of the dizzy is connected properly and that its insulation is in good shape. If you are testing this by cranking the engine, make certain that the dizzy shaft is actually spinning. You don't have to crank the engine to test this, just turn on the ignition and manually open the points. When the points break (spark) the coil should fire.

[jcox]

check on all... man this is getting frustrating. I do have another question. I was testing the coil by running a wire directly to 12v (+) battery to (+) coil and then running wire from coil (-) and tapping to ground with switch on and I do get spark. So the coil still checks out OK.

As I was doing this I ran a test light from battery (+) and started just probing around the distributor and coil areas. I get continuity from all points coil (-) and (+), both ends of ballast resistor, black wire running from coil to dizzy and all areas of dizzy (even the housing). I don't know much about the electrical principals so my question is whether or not this is normal? This is all with the ignition in the off position.

[Force Fed]

Just to be sure of what you are saying:

The single wire running from the distributor is connected to the - terminal of the coil, and the coil + terminal has power to it w/ the switch on?

It's points, so there's only so many things that it can be. My thought is that the points are bad or dirty, or not adjusted right. With the cap off, have someone turn it over while you watch the points. They should open just enough to break contact. I think like somewhere around .016-.018" is the correct setting, at least on most points-type ignitions I've dealt with. If they don't open, re-adjust them so they do.

If they do, but there's no spark, try filing both sides of the points where they make contact, sometimes they get a build-up of corrosion that prevent spark from going through. If that doesn't work, than either the condenser or the points themselves are bad, or both. Usually they get replaced as a set.

[jcox]

I do get 12v to the coil (+) and the coil (-) is going to the dizzy. So maybe I am stupid when it comes to this stuff. At this point I am just trying to verify that I'm getting fire from the coil. Will points prevent simply getting fire from the coil? I'm taking a very simplified approach with one step at a time to resolve the issue. I just want a spark from the coil, I'm sure my questions about points will soon follow. Thanks.

[Force Fed]

Yes, if the points are bad, you will not get spark. The points are the trigger, if they don't work they will not trigger the coil to fire.

[jcox]

so not all hope is lost... I will check the points and let you know. Thanks

[EScanlon]

Also check that little ground wire from the point plate to the distributor body that is on the INSIDE of the cap. If that wire is broken, and it is a very thin wire, it will not allow proper grounding of the points and you won't get spark either.

As Rick mentioned on the other thread, check the condenser also.

Enrique