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240z ignition help

240z Points Ignition Troubleshooting

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#1 280znewbie

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Posted 14 June 2016 - 10:12 AM

I picked up a 71 manual 240z. I can't get any spark from it at all. I have check the points gap which was .018. I have voltage to positive side of coil at both key on and start position. I have used a ohm meter to check that the plug on the distributor is grounded and it is when the point is closed. I have full battery voltage at the negative side of the coil as well as the wire from the coil to the cap. What would be the issue? A condenser of some sort?

Edited by 280znewbie, 14 June 2016 - 10:18 AM.

z cars are the passion and the driving force of us all

'76 280z 2+2 l28et on factory computer.  sunset pearl paint, original interior, factory 4 speed, fun weekend cruiser and nationally awarded show car

'74 260z coupe.  factory l26 and 4 speed, swapped to 240z carbs, roll bar, ready for flares, coilovers, and sway bars, future autocross car

'70 521 mini truck, original 250k miles, l16 and 4 speed, shop truck


#2 NewZed

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Posted 14 June 2016 - 01:40 PM

Pints work by opening and closing, breaking and making the circuit to ground for the coil.  You can test the ignition system with your finger by closing and opening the points with the key on.  If you set the gap when the points are supposed to be closed, they'll stay open and you'll never get a spark.

 

Find a source on the internet that explains Kettering ignition systems.  Your statement below doesn't make any sense.

 

" I have used a ohm meter to check that the plug on the distributor is grounded and it is when the point is closed. "



#3 280znewbie

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Posted 14 June 2016 - 04:19 PM

What I mean is that the point itself works perfectly. It opens to its correct gap and makes contact when closed. On a point system the distributor is grounded and when the arm makes contact it too grounds out. It's what allows the coil to enter it's second phase and build voltage for the spark correct? I've researched the wiring of this system and have verified almost everything to be right using a voyage and ohm meter but yet I get no spark out of the coil and what I'm wondering is the negative post on the coil as well as its output supposed to have 12v? I wouldn't think so

z cars are the passion and the driving force of us all

'76 280z 2+2 l28et on factory computer.  sunset pearl paint, original interior, factory 4 speed, fun weekend cruiser and nationally awarded show car

'74 260z coupe.  factory l26 and 4 speed, swapped to 240z carbs, roll bar, ready for flares, coilovers, and sway bars, future autocross car

'70 521 mini truck, original 250k miles, l16 and 4 speed, shop truck


#4 NewZed

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Posted 14 June 2016 - 05:09 PM

Sorry, but you're not understanding the principles of electricity.  The coil has continuity from the positive post to the negative post.  They're connected.  Therefore, when the positive post has voltage so will the negative post.  If the points are open, they'll be exactly the same because no current is flowing.  One side of your points should also have the same voltage.  Measure battery voltage with the key off, then measure at both coil terminals and the points with the key on.  Measure resistance to ground on the other point, the one with no voltage, to make sure you have a good ground.  You can also measure resistance to ground of the capacitor/condenser.  It should not have continuity.  With the key off, measure resistance of your coil also, from the neg post to the pos.

 

If all of the parts measure right, and you get them connected right, you should get spark.

 

There's stuff on youtube that shows all of this.  Points ignition systems are common to all brands of cars.



#5 280znewbie

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Posted 14 June 2016 - 06:21 PM

I do understand electricity, done plenty of car rewires, just new to point systems. I have measured those thing, i.e. ground is good, voltage at one side of point, the only thing left is the condenser, u say it shouldn't have continuity to ground correct? It is wired on the distributor to negative coil post wire correct?

z cars are the passion and the driving force of us all

'76 280z 2+2 l28et on factory computer.  sunset pearl paint, original interior, factory 4 speed, fun weekend cruiser and nationally awarded show car

'74 260z coupe.  factory l26 and 4 speed, swapped to 240z carbs, roll bar, ready for flares, coilovers, and sway bars, future autocross car

'70 521 mini truck, original 250k miles, l16 and 4 speed, shop truck


#6 NewZed

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Posted 14 June 2016 - 06:46 PM

How are you checking for spark?  Maybe you left the rotor off?  It happens.



#7 Mario

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Posted 15 December 2016 - 08:07 AM

lol yes it does do not ask me how I know hahahaha. I would replace the condenser







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