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austinnelson117

1971 240Z Not Getting Spark

24 posts in this topic

Hello all, I have gotten my Z to the point where it is time to turn it over and see what happens. So far nothing. It is not getting any spark at the plugs or at the wire coming out of the ignition coil that leads to the distributor. I tried to follow the wiring from the Haynes manual but it shows only 1 positive wire at the ignition coil and I have 3. 2 of them beep on the multimeter ONLY when the ignition is turned and the third one beeps at all times. Then I have one negative coming through the wire bundle as well that connects just above the distributor. I am getting power into the ignition coil just not out of it. What am I doing wrong here??

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Or does anyone have a wiring diagram besides any that google show, or that are in the book? Maybe some pictures of your stock engine? All of the wires are live, it's just a matter of hooking them up correctly. We have yet to find a decent wiring diagram. We tried our brains and messed around with different combinations, but nothing seems to get it to spark.

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ID: 4   Posted (edited)

Additionally, Hanes manuals are useless. You can download Nissan's Factory Service Manual at www.xenons30.com.

That said, a points ignition system is pretty simple. With the ignition on, you should have +12 constantly to the + post of the coil. The points in the distributor are like a telegraph key and will alternately ground and lift the ground to the (-) post of the coil. When this happens, a spark will be generated. If you connect the black probe of your multimeter to ground and your red probe to the coil's (-) post, you should see the voltage fluctuate between +12 and 0 as the engine slowly cranks. (Well, there might be a drop resistor inserted in there, so maybe these are not the correct figures, but it will fluctuate.

If the voltage is fluctuating, but you have no spark, then your coil is bad. If the voltage isn't fluctuating, then something might be wrong with your points.

Edited by FastWoman

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Thank you for that. The schematic helps.

Maybe someone will read this and understand....

-At the location of the ignition we have a green wire with a white stripe that is ONLY active when we turn the key.

-2 Positive black wires with white stripes.

-Yellow wire that grounds to engine

-Black wire that looks like it would connected to the distributor as a ground, but while testing for complete circuits, we couldn't find a reason to call that location a ground.

We also had what looked like a small capacitor/condenser that was sitting around. Maybe we need to use that?

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Don't forget to adjust the points. They have to close and open to make and break the primary circuit in the coil. The condenser will stop your points from pitting and give you a stronger spark but is not necessary.

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There is an important detail missing. Is this a stock ignition system? If so, have you checked the gap & dwell on your points?

For a stock system

In the start position, the green/white wire is energized from the white/red wire at the ignition switch. It goes through the tachometer and on to the black/white wire that goes to the positive side of the coil. In the run position, there is a black/white wire that is energized from the white/red wire at the ignition switch. It goes through the ballast resistor (dropping down to about 9 VDC) and on to the green/white wire.

The black wire does go from the coil to the distributor. The ground you are looking for actually goes through the condensor (capacitor). It would go off of the negative side of the coil.

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First thing that came to my mind is your points aren't opening. As others have suggested, check point gap.

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Ok well I'm not 100% sure what is and isn't stock, the previous owner did mention something about switching over to electronic ignition but I'm not sure exactly what was done. I will probably call him this evening to confirm. But, according to your description of the wires everything sounds about right. One problem we had was the ground on the distributor that connects to the coil was not reading when the other end of the multimeter was connected to the positive battery terminal. We just made our own ground for the time being just to test it but im not sure if that has anything to do with the problem. Also, where does the green/white wire connect to the ignition set up? We followed the manual to a T but came up blank. And Steve, we are learning as we go here but I have no earthly clue how to check the gap and dwell of the ponts. Do you mean the gap on the spark plugs? I will do some reasearch to try and learn a little more about it but like I said we followed every wiring diagram we found exactly.

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Did you download the FSM yet? It's all in there. Get the '72 FSM from Xenon's site that you've been linked to and is in Steve's signature. Everything should be similar, if not identical, to a stock '71, especially reguarding the ignition system.

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The FSM is not just good for the wiring diagrams, but also for everything else concerning the Z. Don't know what's stock? Check the FSM. Don't know what point gap is? Check the FSM. Googling terms you don't know (like point gap) will help.

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Ok I do see one difference in the wiring of the link Alex posted and the one in the Haynes manual. Will check that when I get home. But, as far as the contact points go, do distributor rotors come with new contact points, if so would it be worth my while to just get a new one since the car has not been driven regularly since the 90's?

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Ok well I'm not 100% sure what is and isn't stock, the previous owner did mention something about switching over to electronic ignition but I'm not sure exactly what was done. I will probably call him this evening to confirm. But, according to your description of the wires everything sounds about right. One problem we had was the ground on the distributor that connects to the coil was not reading when the other end of the multimeter was connected to the positive battery terminal. We just made our own ground for the time being just to test it but im not sure if that has anything to do with the problem. Also, where does the green/white wire connect to the ignition set up? We followed the manual to a T but came up blank. And Steve, we are learning as we go here but I have no earthly clue how to check the gap and dwell of the ponts. Do you mean the gap on the spark plugs? I will do some reasearch to try and learn a little more about it but like I said we followed every wiring diagram we found exactly.

There is 1 wire going from the negative coil terminal to the terminal on the side of the distributor. The condenser connected here with a short black wire as well. The terminal goes through the distributor housing and connects to the points with a short wire. The feed-though on the distributor should be insulated from the distributor housing.

As has been said, the negative terminal on the coil should be 0 volts when the points are closed and +12 volts when the points are open. Measure this with respect to ground, not the positive battery terminal. If the voltage is always 0 you have a short, incorrect wiring, bad condenser, or the points are adjusted wrong. If the voltage is always +12 the points are not closing or the wire going to the distributor is not connected.

The green/white wire connects to the ballast resistor. On the same terminal there should be a black/white wire. The other terminal on the ballast resistor should have a black/white wire. If the 2 black/white wires are reversed the car will run but the starter bypass won't work possibly making the car hard to start.

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Ok well I'm not 100% sure what is and isn't stock, the previous owner did mention something about switching over to electronic ignition but I'm not sure exactly what was done.

And Steve, we are learning as we go here but I have no earthly clue how to check the gap and dwell of the ponts. Do you mean the gap on the spark plugs? I will do some reasearch to try and learn a little more about it but like I said we followed every wiring diagram we found exactly.

Points are not used on an electronic ignition. That is why I said "IF". They are not spark plugs.

Points look like this the first picture below. They reside under the distributor cap and rotor.

The second picture is a 280ZX ignition. It is commonly used by people going from the stock ignition to an electronic ignition. Other common upgrades to eliminate the points are a Pertronix ignitor and Crane ignition. Use Google to find examples of those.

While there are some deviations between the wiring diagrams and real life, the FSM wiring diagram is the most accurate source for stock wiring. As far as the wire colors and where they go, I pulled those STRAIGHT off the FSM wiring diagram. The only exception was mentioning the condensor. If you have an electronic ignition, you'll need to 1) figure out which ignition system you have and 2) search for how it is supposed to be wired.

post-5413-14150816597465_thumb.jpg

post-5413-14150816597914_thumb.jpg

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Ok we wired everything up according to the FSM and still no spark from the coil. But, we did get spark at the point in the distributor. Why would we be getting spark at the distributor but not the coil? And the coil reads 12 volts at both the positive and negative terminals on the coil at all times like we mentioned earlier. Does that mean that the point in the distributor is not closing? And if not how do we get it to?

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Btw, the points gap is sparking when I manually open it with a screwdriver and the key is in the on position.

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First thing that came to my mind is your points aren't opening. As others have suggested, check point gap.

Have you done this yet?

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Secondly, read up on how breaker point ignition systems work.

I don't get how you can try to solve something without first understanding how it works. We've pointed you in the direction you need to head to, but the work must be done by you. Otherwise, you're just going to have others solve your problems for you without you learning a whole lot about what is actually going on (this is how a lot of "internet myths" begin, BTW). Asking a well-researched and thought out question is great, so read up on the fundamentals of what you're working on as you will learn a lot more than by just staring at the engine and guessing how things work.

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Forum etiquette says that you should tell the people that helped you out how you solved the problem.

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My apologies, I just now got done working on the car for the day. As it turns out, the ground connection on the side of the distributor that was not reading on the multimeter before, randomly started to pick up a reading today so I reconnected everything as it was and viola I had spark. I can't really explain what happened because I did nothing but disconnect everything, let it sit overnight, and reconnect today. I ended up having to re-time it and she started up instantly with no trouble for the first time in 15 years. She ran like a champ and smoked up my garage really good. Thanks everyone for all of the help. Now on to the next thing!

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Guys this thing sounds like an airplane. Open headers are awesome.

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