# PL 521 really strange Ignition Coil Problem



## SirSedrith (Mar 24, 2011)

Hey dudes. 

Quick question, if you please. ive called mechanics, friends, dads, friends dads, uncles, neibhors, etc. Im at a total loss. OK, 

There is no spark at the spark plug when i pull the plug, ground it to the valve cover and turn over the engine. when i pull the spark plug away from the cover, I believe i Max out the Coil, forcing it to work harder, and then i get a spark from the plug to cover. Replacing the plug, i can do the same thing at the distributor, pull the coil wire from the cap, create a gap, and the engine runs pretty well. the timing may be off a bit, carb not totally dialed in etc, but itll run rather well. 

the points are adjusted. 
the spark wires are new,
the plugs are relatively new,
cap and rotor are new, 
points are new.
The Coil is NEW as well, which is what people are telling me was the problem, but now there is a new coil. 

so............. There we are. I need to get back to work and that truck is my ticket. 

Any Ideas?

Peace.

:lame:


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## jdg (Aug 27, 2009)

Points may be adjusted, but not correctly. Just setting a "gap" isn't good enough, you have to set the correct dwell time using a dwell meter. If that's not the problem, then check the condenser, which is usually in the same area as the points, or quite often, part of the points assembly.


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## SirSedrith (Mar 24, 2011)

the points were gaped correctly, they are there to break the circuit on the ground wire of the coil, to let the coil pulse to each of the spark wires, right? even when they were way to open, a while ago, the truck ran ok. then i got out a feeler guage, set it to the center measurement ( between 41 to 51 mm or whatever) and squeezed the points onto the guage. then i tightened them. and then felt the gap and it felt right. it was running at that point. 

i thought the dwell was something you adjusted after the engine idles regularly. please correct me if i am wrong.

as for the condencer, that sounds possible. there are three, one on each ground wire that comes from the points to the coil. another attaches onto the positive tab of the ignition coil. its something i havent checked yet, do you have an idea on how to check that? im pretty sure thats not discussed either, but ill look.

thanks for the response dude,
ill try what ya said and let me know what ya think about the dwell. if i cant get it to idle i dont know how.


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## jdg (Aug 27, 2009)

I know what points do and how they work and why they work the way they work and various failure modes involved with points.
Setting points with a feeler gauge only gets you "in the ballpark". On some engines, this method might be good enough 99.99% of the time. Yours might be one of those types.
You can have X amount of breaker point opening and have dwell times that are out in the weeds, in either direction, depending on the types of points and the way they're set up.


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## SirSedrith (Mar 24, 2011)

thanks for writing back!
sorry there, i was really talking to myself and letting you listen to see if I understood it, not the other way around, i wasnt trying to tell YOU what they do, i have no doubt you know! : ) 

i also didnt know there were different kinds of points, for one vehicle, though it dosnt surprise me too much. uhhh.... i guess i have the type of points that go with the truck. i dont know how else to describe them. 

so the feeler gets you in the ball park.. ill be damned. OK

so what is next? 

i have a dwell meter from the pawn shop, not sure if it works, id like to test it on another truck but dont know how thats gonna happen.  

i read the instructions on how to check the dwell on ehow. it says to get the engine warm. 

im not sure how i can do this as i cannot get spark to the cylinders normally. im also surprised that it says to check the dwell and THEN do the timing. interesting.

can i do it cold, er outside temperature and just crank it with the battery?
if i can do that then i might be able to measure the dwell. if the meter works.


thanks again, jdgrotte.


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## SPEEDO (Jun 9, 2003)

do you have the duel point set up? or the single? (you mentioned more than one condensor)
I had the duel set up in my 510... at times, it could be fun to set them


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## SirSedrith (Mar 24, 2011)

yup, awsome dual point system. Please dont think i am rude when i ask, Does that matter at this moment (i ask out of ignorance) cause i thought the second point opened at high revs when the vac advance was activated? dosnt that mean that the second point serves no purpose when starting and idling? 
I.E. only the first breaker point enters this particular equation? ( if im wrong for the love of Jake tell me!)




So in my thinking, we have established these facts. 

when i over-work the coil i can get it to run.

it maybe the condensor(s).

it may be the dwell, but the engine has to run and warm up first.
( do you have any ideas on that last issue? im lost as how to preform this without it running)

? the dual points? 

what else can i test to tell me WTF is going on? 

There has to be another thing that will define this problem in sharper detail.


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## jdg (Aug 27, 2009)

> sorry there, i was really talking to myself and letting you listen to see if I understood it, not the other way around, i wasnt trying to tell YOU what they do, i have no doubt you know! : )


It's all good...



> so the feeler gets you in the ball park.. ill be damned. OK


And in a lot of cases, is just perfectly fine. But, if the stars are aligned just right, then dwell matters (and if the book says it matters  )



> i have a dwell meter from the pawn shop, not sure if it works, id like to test it on another truck but dont know how thats gonna happen.


If you can find another V-8 with points, it should read 29-31 degrees, usually (some might be different).



> i read the instructions on how to check the dwell on ehow. it says to get the engine warm.


Warm, cold, idle, fast idle, full throttle, shouldn't really matter as far as dwell goes.



> im also surprised that it says to check the dwell and THEN do the timing. interesting.


Dwell affects timing because you're changing the point at which the points open. Timing doesn't affect dwell because you're spinning the whole points assembly when you adjust timing.



> can i do it cold, er outside temperature and just crank it with the battery?


It's supposed to be done by just cranking the engine...that way you can crank it, read the meter, adjust it, crank it, read the meter, adjust it, and so on...



> Does that matter at this moment (i ask out of ignorance) cause i thought the second point opened at high revs when the vac advance was activated? dosnt that mean that the second point serves no purpose when starting and idling?
> I.E. only the first breaker point enters this particular equation? ( if im wrong for the love of Jake tell me!)


Dual point systems are there for greater "dwell time". A single point system can't handle the longer "dwell time" at high revs without the points bouncing. With a dual point system, each set of individual points only has to stay closed, say for sake of argument, 60% of the time. In this case, there would end up being a 20% overlap.
Both sets of points are closed, the first set opens, but the second set is still closed, then the 2nd set opens, SPARKY!, then right after that the first set closes again.
If you only had one set of points, at high revs that set would open, then a split instant later, have to close again. With 2 sets, you can split that time between the two. It's all about the mechanical limitations of the metal used in the points themselves.




> when i over-work the coil i can get it to run.


Not so much overworking the coil, but maybe the problem is giving the coil's magnetic field enough time to collapse (i.e. points open) to create enough voltage for the spark. By introducing another gap (opening) in the system, you're forcing the coil's magnetic field to collapse later.



> it maybe the condensor(s).


If the condenser was shorted, and/or had less resistance across it than completely open-circuit, it may be causing the magnetic field in the coil not to build up completely.



> it may be the dwell, but the engine has to run and warm up first.
> ( do you have any ideas on that last issue? im lost as how to preform this without it running)


Only if your "book" says so specifically...

Of course, that's only my opinion...I could be wrong in the end...but it makes sense to me.


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## SirSedrith (Mar 24, 2011)

OK! Ill report back when its light out and the battery is charged again. i just found a mechanic a block away, stead of 4, so i can carry the battery. yea!

i found the angle in the book, i forget but ill read it again. 

the dwell adjustment makes sense to me now with that last explaination. 

I got one new condensor and will look for another two (there are three, two for the distrib, one for the coil) with the same specs as stamped on the old ones.

i see, both points work at the same time to do the same job with an overlap in opening and closing, like pistons that work in sequence, but closer in time. (well now that i think about it not quite the same but, eh.) 

Something else i just saw in the book and is not explained is where the two spade connectors come from the dis, that connect to the - side of the coil have a jumper wire strung between them, and on mine there is no wire. both wires coming from the spade connector (from the points) right now connect to the - pole anyway, im not sure if it makes a difference but ill try it out. couldnt hurt. 

if i understand making a gap with the wire is like adjusting the dwell on the points. extending time. kinda. 

We shall see. 

no matter what result, thanks so much. i was totally at a loss for what to do, atleast doing SOMETHING is better than being frustrated. and eventually the problem will resolve when every freakin part is replaced or repaired or adjusted correctly. 

peace


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## jdg (Aug 27, 2009)

Yep, close enough. And if I can add one thing...
Dual point setups are all fine and good and all. A good set of well tuned points can run just as good as anything else in the world...but...
An electronic ignition solves and/or avoids Soooo many issues that points have. If somebody makes an aftermarket electronic distributor/ignition type setup for your rig, that's the way to go.
In my case, a '74 Chevy Malibu with a 350, it had stock points. I got tired of replacing/adjusting them every 5,000 miles, went to the junkyard, got an HEI distributor out of a '76-Chevy-something, and the only change I had to make, other than new plug wires, was to bypass the ballast resistor (which you may or may not have, and come to think of it, if your ballast resistor is bad, you'll have all sorts of headaches).
No points to wear out, dwell is "automatically" set by the 'electronics', more voltage can be passed to the coil, more accurate timing, zero chance of points bouncing at high revs, and so on...


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