No spark WHILE cranking?

[kayinsunz]

Hi all, have been reading these forums for a long time but first time poster. Happy to be here

I bought a 71 240z that was sitting for 4 years. Engine is complete, and cranks well but does not start. I already suspect a carb rebuild... But I thought I'd start with spark. When I first got the car in my garage I noticed no spark at all from the coil to the valve cover, cranking or not. Saw that the guy i bought it from wired the Pertronix Ignitor negative wire to the positive post on the coil, and the positive wire from the Ignitor to the ballast resistor. Since its a 3ohm coil, I wired the Ignitor properly to the coil.

Now the coil wire does not spark to the valve cover while cranking, but as soon as I let off the key it sparks strong 1-3 times. 

I have replaced the ignition switch, rotor, coil, and dizzy cap with no avail. Jumped the battery to the Ignitor and still, same condition.

 

Next steps are new Ignitor, and new starter.

Any suggestions will be greatly appreciated, thanks for having me on the forum.

 

[munters]

To me it sounds the ignition switch start batterie power and ignition switch batterie power are mixed up.

I had the same Problem with a new ignition switch. You can power the coil directly from bat+ with a patch cord to verify. Keep in mind the engine will not stop when you turn the key to off position.

[Zed Head]

Stop replacing parts.  There are two circuits to the ballast resistor and coil.  One for Start and one for Run.  Sounds like your wire for the Start circuit is either not connected or connected incorrectly.

Here's the diagram showing the ignition switch wires. Green with a blue stripe would be the Start wire. - 

Edited June 12, 2017 by Zed Head

[kayinsunz]

6 minutes ago, munters said:

To me it sounds the ignition switch start batterie power and ignition switch batterie power are mixed up.

I had the same Problem with a new ignition switch. You can power the coil directly from bat+ with a patch cord to verify. Keep in mind the engine will not stop when you turn the key to off position.

I forgot to mention that I tried that as well. But, I'll have a look at the diagrams and see what I can find. Thank you sir.

 

[kayinsunz]

7 minutes ago, Zed Head said:

No offense - stop replacing parts and start understanding how they work.  There are two circuits to the ballast resistor and coil.  One for Start and one for Run.  Sounds like your wire for the Start circuit is either not connected or connected incorrectly.

I see what you mean. No offense taken. On the ballast resistor, in the start circuit on the headlight side or the firewall side? I'll run through the service manual again in the meantime.

[Zed Head]

I think that the diagram is a little misleading.  I don't have a 71 but on my 76 the wires are connected at the ends of the ballast resistor itself.  One at the end that passes through the resistor and the other one directly to the end that then goes to the coil.  So, in the vicinity of the coil and ballast you should see the green/blue and the green/white wires.  Your green/blue might not be connected, it's the Start power.  

You didn't say what happened when you tried munters suggestion.  Just that you tried it.

[Zed Head]

I should actually step out of 240Z world.  It's confusing.  Still, there's a Start and a Run.

 

[kayinsunz]

Right, well I jumped the coil to the battery and get the same condition. I'm going to check the ballast resistor now and see if my GW wire is loose or disconnected.

And call me a dummy but these '71 diagrams look like a maze of matrix code lol.

Thanks again for the assist Zed.

[Zed Head]

42 minutes ago, kayinsunz said:

Saw that the guy i bought it from wired the Pertronix Ignitor negative wire to the positive post on the coil, and the positive wire from the Ignitor to the ballast resistor. Since its a 3ohm coil, I wired the Ignitor properly to the coil.

as soon as I let off the key it sparks strong 1-3 times. 

Final thing - actually, what you need to do is get a meter or a test light and measure voltage at the coil terminals while at Run and Start.  You might find that you have power but that the Ignitor is damaged and not breaking the circuit correctly.  You'll always get at least one spark when the power to the coil is cut.  That's how coils work.  Don't know why you'd get three but anyway... Use a meter or light and verify power.

[Zed Head]

4 minutes ago, kayinsunz said:

Right, well I jumped the coil to the battery and get the same condition.

Sounds like your Ignitor is damaged.  There's a test/check procedure for the Ignitor.  Ground is important also.

https://static.summitracing.com/global/images/instructions/pnx-1281.pdf

Edited June 12, 2017 by Zed Head

[kayinsunz]

Well, I have a new one on the way from ZcarDepot. But I just checked the wiring setup to the ballast resistor and GW wire wasn't connected to the resistor at all, it was connected to the ground side of the coil. Going to strap it to the Start power side of things. Will post results.

[sweatybetty]

1 hour ago, kayinsunz said:

 its a 3ohm coil

 

 

iirc, the 3 ohm coil does not use a ballast resistor