Car Won't Start, ignition system problems!

[Seanh]

Last night on my 72 240z I thought my coil went bad. After sitting for about a half hour last night it wouldn't start up again. I towed it home and looked it over. It wasn't getting any spark at the plugs, so I checked the coil wire. Won't jump harldy any gap, couldn't even see a visable spark unless it was touching the block. So I checked power to it. Oddly, it had 12 volts at the negative end, and nothing at the positive end. So I bought a new coil this morning, put it on, wired up just like the old one, and still no starting. I need 2 people to check spark, so I can't check it yet, but I did check power. Were back to haveing 12 volts on the positive side of the coil and perfect grounding on the negative side. I just don't understand what could be wrong here? The positive is the side that just has one wire correct? And negative is the side with 2 wires, one going to the car, and the other to the resistor right? Perhaps the resistor or whatever that thing is, went bad also? Do I need to replace it? What do you think I should check now?

[Seanh]

I also just tried hot wireing power to the coil directly from the battery, and still nothing. So I'm thinking it has to be a grounding problem, I think? Could it be that stupid little resistor thingy? Thanks

[Seanh]

Something else I just noticed, I don't know whats going on or if this is normal. When the car is shut off, the coil isn't really gounded totally, theres a little resistance, about 6 ohms actually. But when the ignition is on, its grounded totally with 0 ohms. However, useing a test light, while the car was turned on (but not running obviously) there is a backfeed of power thru the negative side of the coil. While yes, it is perfectly grounded, I get a test light to come on dimly if I touch it to the negative side while its on. Is this normal or whats going on? I'm thinking perhaps I have another problem somewhere else in the car? LMK what you think?

[Daniel]

check your points.If they are burnt or worn out /bad gap/stuck closed etc.Then your coil cannot saturate.As for the ballast resistor you can wire across it as a test.When you turn the key to the start position it sends 12v to the coil.When released and in the run position it uses another wire that runs through the ballast resistor to drop the voltage and save the life of the coil.A short test won't hurt it.All that resistor is is a strip of stainless steel.Also check the small ground wire inside the dist.You'll see it when you look at the points.Its about an inch+/- long.Make sure it has good clean no oxidized connection.NO !!THE POSITIVE IS THE TWO WIRE(now you know why) Have fun!!! Daniel

[Seanh]

Alright, I also just learned the difference between the coil resistor and the condensor.

Points look alright, but I didn't check the ground wire, I will do that.

However you said the positive side has the 2 wires...Which wires is it supposed to have? I would assume its supposed to have the wire that is getting 12+ in the run position and the condensor also? Is that correct? Thanks

[Seanh]

Alright, back again. When out and checked that ground wire you were talking about...Appears to be pretty messed up, along with my points. The grounding has a sleeve on it, its all shreded and torn up. After looking over it again I noticed some other things too. There appears to be 2 ground wires in there. One is tword the front, that goes between the springy part of the points and the condensor. The other is to the back, near the vaccum advance and goes between the screwed down metal part of the points to the distributor body, this wire is in great shape. The first one is the one thats torn up.

I plan to go down to the store and buy a points tune up kit for it. How do I do about setting the gap and everything? I'v never worked with a points distributor before, so I don't quite get it. If someone would be kind enough to go thru the procedure of setting it all up I'd be very thankful. Thanks!

Also, one more thing...I probally messed up on saying this before. On my coil, I have 3 wires plus the coil-distributor wire. Alright, one wire is ground, one is 12+, and the other goes to a condensor looking thing that is bolted onto the coil bracket. Where does the wire to this go? It used to be hooked onto the negative side, and had been working fine up until now, but then you said that the positive side should have 2 wires? So which is it and what is this thing anyway?

[Seanh]

Most of you probally thinking I'm pretty stupid right now, and yeah, I am...So heres a couple pictures I took (thank god for digital cameras) of what I'm talking about...

In this picture you can see the distributor...That wire in the upper left corner is the one thats all shredded and torn up...

[Seanh]

This is the shot of the coil and that stupid little condensor looking thing that I have no idea which side to hook it to? (Sorry about the size, I'm on my crappy computer that has no photo editing software...)

[Daniel]

O.K. the black coil wire is coil neg.It goes to the dist.The black/white is positive.The condensor on the coil is an effort to stop radio static noise,it has nothing to do with any function of the vehicle.As far as the point install,myself I remove the dist.(old worn out back, I don't bend like I used too.)On one side of the dist is the timing marks and pointer.NOTE THESE.On the other side is a single screw in a slot.Remove the screw and wiggle the dist up.These cars are great.An american car you must line up the timing gear.Not these.The dist bottom has a V shape and will only go back in the correct easy to do way.Remove the two point holding screws and replace.Turn the dist bottom until the cam in the center is at the high side of the lobe.Use the little slot with the screw in it and adjust the gap.0.45mm to 0.5mm.Tighten the holding screws and recheck gap.While your in there I like to use small wire brush or a razor blade and scrape those ground connectors and their mating surfaces.That way I know I have nice fresh surfaces.The condensor on the dist. is used to absorb some of the current that is looking for a place to go when the points seperate.When they go bad it causes the points to burnout and pit/weld.Of course as point wear they do pit as normal .When reinstalling put the rotor on and wiggle it to set the dist.Be very careful when removing that dist screw.These are notorious for breaking.I first tighten it A LITTLE!! then loosen a little then run it back down alittle.This in and out motion clears the threads and will save you alot of grief.Set the timing back to where it was and reconnect stuff.If you don't feel good about dist.removal you can get the points on the lobe by putting the car in 4th gear and rocking it back and forth.

[Daniel]

From you photo it looks like the fiber piece that rides on the dist cam is worndown.Most of the ones I have used appear to have more meat on them but its hard to say.I would start by trying to adjust the point you have to correct gap and see if it starts.At least then you know your OK.Also another reason I remove the dist is to clean out all that dirt like you have.I would still remove and clean those grounds as I described.My guess is it was last done was sometime in the 70's huh?What about the age/status of your coil/plug wires?

[Daniel]

Just a guess but the power to your test lite may just be the dist.condensor discharging through your lite.If you don't have a feeler gauge the old shade way was to used a match book or business card to gap the point as a rough guess.Of course this is a temp measure.We want nothing less than correct.

[Seanh]

Alright, I shelled out the whole 4 bucks and got a points kit. Put it in, wired everything up correctly, set gap as best I could...Started up finally...but ran like ****. So I gave it some gas and it stumbled and finally died...I don't know whats going on anymore, I set and played with the gap atleast 20 times, and tired takeing it for a drive, and it died and had one hell of a time getting it back home. I pulled a plug, and they are pretty nasty (about 30 days old) but I guess that could be contributed to trying to start it last night and fouling the plugs or somthing. But yeah, the gap is correct, and it doesn't run worth a ****...The plugs, wires, cap, and rotor are all 30 days old, not 30 years...I was on my way into town to get some new plugs, but obviosly didn't make it...What should I do now? I looked at the points and on the old one I replaced it looked like it had corrosion on it, some green crap covering the end of the arm...Now, on my new ones, after running the car probally a total of 20 minutes, its starting to look like its getting the same thing happening to it...What the hell is wrong? Condenser perhaps? I didn't think it would screw up the points this fast, but maybe so? Why is it running like crap? Plugs maybe? LMK Thanks