1971 240Z Not Getting Spark

[Alex K]

Posting this so I don't lose the link...

http://www.classiczcars.com/forums/showthread.php?41386-73-240z-No-spark-from-coil

^ has a lot of good information.

[austinnelson117]

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?

[beermanpete]

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.

[SteveJ]

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.

[austinnelson117]

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?

[austinnelson117]

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

[LeonV]

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?

[LeonV]

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.

[austinnelson117]

I already did plenty of research. And the problem is now solved.

[Zed Head]

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

[austinnelson117]

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!

[Alex K]

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