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New member...79zx ignition problem


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Hello to all fellow Nissan/Datsun enthusiasts! I am happy to be aboard. I am having an issue with my 79 Zx. I was working on it recently and inadvertently tore up a small resistor that was in place by the coil...it looks like a small battery on its side with wires coming out of both ends...I read that it is a resistor that was originally used for noise suppression, part #: 47DO-D16? I am trying to find out 3 things, what exactly is it? Do I need it? If not, how do I bypass it? It’s not a part of a “points” system within the distributor, all I know is the car will not crank without the resistor hooked up. Thanks in advance!

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That should be a condenser and it is used for noise suppression as you've stated. I'm not certain what the rating is in Farads for the original unit, maybe someone can chime in and help point you to a replacement. Your car should still crank without the condenser connected so if you're having a no-crank issue it may be due to something else dealing with your ignition system. The 70-78 Z cars had a ballast resistor for the ignition coil that needed to be connected for the engine to start, but your 79zx uses a matchbox distributor and should not have any sort of ballast. 

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Crank.... verb, to turn an engine over with a starter. If it won't 'crank' then the battery is dead, wire off, bad starter, bad ignition switch.

If the starter turns the engine but it doesn't start then it's said to simply... not start or won't start. 



Can't find anything like you describe on the zx coil or ignition, nor should there be. Points distributors often have noise suppression condensers but are single wire with the outer case clamped to ground and are found beside the points. The  lats 240Z to use points was '73, all were some form of EI after this.


What you describe sounds like a ballast resistor and without it the engine will fire up while turning the engine with the starter but will stop when the key is returned to ON. Again this is NOT used on a '79 zx they were all EI electronic ignition. All non turbo were EI and all turbo were CAS crank angle sensor. 


 A picture would help

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OK, I bought a ballast resistor, plugged it in, and behold, it cranked....I should state that it always turned over, but would not fire. I'm trying to post pics but having a problem figuring out how.  I got it cranked....I have another issue...after I crank it, I can occasionally hear a medium pitched whirr, and when I hear it, my voltmeter is pegged....above 18....what could that be? Thanks for the help fellow Datsun lovers....also, how do I post a picture?

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I can only assume that you have an earlier engine swapped into your zx. Or you are running a points coil that needs a ballast. The fact you are producing 18v from the alternator further proves that you have an external regulated alternator (last used in '77) on a car that uses an internal regulated alternator and there isn't one. I wouldn't run it until you solve this. Running at 18 volts is hard on things designed to run on 12. It will boil the battery.


Look behind the oil dipstick on the top of the block just below the head. What engine size is stamped there??






fb9yF51.jpg L24, L26 or L28?


Driver's door jam tag.. what's the build date???


Take the distributor cap off. Do you see this...



Or points...



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1 hour ago, Ronbuck1 said:

How do I get some attachments into the "insert existing attachment" folder?

 You will need to get an account with a picture hosting site like, (but not limited to) imgur. Do NOT use Photobucket. These sites will store your pictures for you. When you want to post a picture go to your picture hosting site album, copy the picture information come back here and paste them in your post. 

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