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73 240 No spark

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  • Author

Ok. That makes sense.  That is what I will do next.  I think I tried to do that originally but had smoother wire also on the green wt terminal. That extra wire was the bw with no power. Maybe it was grounding the green out and stopping power? This is how I tried it in photo. 
oh ONE MAJOR question that may solve my problem.  What is supposed to happen power wise at coil positive to get spark and keep car running?  Constant power ? Only power on start ? 
???????

IMG_8763.jpeg

23 minutes ago, Shawninvancouver said:

What is supposed to happen power wise at coil positive to get spark and keep car running?  Constant power ? Only power on start ? 

There should be power to the coil in both ON and START.

During START, it is wired to bypass around the ballast resistor, and in RUN power is wired to go through the resistor.

OK when you have it wired like I asked in the last post, start measuring for power at the - side of the coil and dizzy with the points open and the key in the run position . Stop trying to crank it over looking for a spark, We know there is no spark, by measuring the voltage path we can help you find why there is no spark.

 

  • Author

Ohhh and for a wired testing of spark from coil. This other nice drawing is how you suggested it? Correct ??

draw2.jpeg

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Yes both are correct, please tell us what the volt reading is on the + of coil, - of coil, the neg point on the dizzy and at the points. Remember do this with the points open and the key in run. And your meter ground connected to the engine.

Not till you confirm you have a good 12 volts getting to the points. One thing you can do if the power is good to the points is rotate the motor until the points are closed and then with something non conductive open the points and see if you get a spark across the points. It is not always visible so you can try a few times pushing them open and then letting them close. If that looks good then try the same thing with a plug wire and plug like in your second drawing and see if you get a plug spark. This is of course with the key in run.

  • Author

I tried yet again with still no spark. 
multimeter tests.  
with key in run position

green white on ballast 12v from other wire across ballast 

black with on ballast 12v

Coil +. 0 v

with key on start coil + has .15v

yes that’s .15v

with key on green white alone has 12v

Still no spark  

 

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  • Author

The coil + wire that is getting .15volts goes back to tachometer  what is the best course of action ??

 

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First thing is how is it that you have 12v at the green wire and zero volts at the coil I thought you hooked up a jumper between the two. What about the other measurements? Did you do the measurements with the points open? I thought we already decided that the b/w from the tach was bad and that’s why I got you to install a jumper from the g/w to the coil. 

  • Author

Yes  I did do the jumper as you can sorta see in photo below   Of course with jumper if gets 12v  as green wt is 12v  still no spark   No sure how this works  the black white on ballast has power all the time  it sends it through the ballast do now the green wt has power all the time and with a jumper the coil has power all the time    ??!

 

IMG_8799.jpeg

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