# Whats that spark?

1. Oct 21, 2012

### fabianek

hi i have come across a post regarding ignition spark in cars with waste spark management.
and my question is... that spark that comes out of that coil or any tesla coil what does it have????is it positive or is it negative or is it something else....
i have come across something that i can not explain as im just ordinary man :) and i need some advice

Ps:what im asking is as far as my understanding that 90 degree spark what does it have is it positive or is it negative ?....
beacuse it goes to both terminals on the battery positive and negative also it doesnt blow gases in the battery so what is it ???? it does fire fuellair mix in the combustion chamber but doesnt blow gas in the battery containing hydrogen ?????wtf?????

i had a faulty spark plug so it was running on three cylinders only . i got that lead off that spark plug and thats when strange thing happend i got this spark jump outside the engine from top of that lead to the tip of that spark plug about half an inch gap and it runs ?..... what i find out later when i got that spark plug out ... ,it was dead short in there as carbon build up in spark plug gap .i was really shocked so i started playing about i stick a nail in that little hole in the lead and i started my car without that faulty spark plug in ... and i got that lead in fourth cylinder and it runs without a bloody spark plug ...... i checked most forum about cars and ignition system and nobody can give me an answer....... pleas help

that spark doesnt blow computer diodes battery or gas in the battery it also fire to both terminals on that battery positive and negative

and funny thing is when i got it fire to aluminium pipe on aircon the car stops..... ??????

its very strange ................

so if anyone of u knows what that spark is pleas let me know coz it cant be positive or negative as it goes to both terminals on the battery ..... :\$
pleas help
cheers
ps: sorry for my english as it is my second language :)
fabian

Last edited: Oct 21, 2012
2. Oct 21, 2012

### CWatters

It's not complicated..

http://en.wikipedia.org/wiki/Wasted_spark

3. Oct 21, 2012

### JustinRyan

sounds like you have tried to blow the battery with a spark plug ?.. maybe the hydrogen needs more oxygen in the mix :-)

4. Oct 21, 2012

### sophiecentaur

My old 2CV had that system. Two cylinders needed no distributor (and no vacuum advance, either). Clever thing was that the cyclinder with no compression (at the time that the other needed the spark) would allow that plug to strike much easier than the one under pressure so it got more than half of the available spark energy.

5. Oct 21, 2012

### fabianek

help help help :)

Last edited: Oct 21, 2012
6. Oct 21, 2012

### sophiecentaur

Try asking your question again but get the main point into a single sentence. It's not clear which particular aspect is most important to you.
(Btw, sparks are not 'positive' or 'negative' - they jump between points with different Voltages.)

7. Oct 21, 2012

### CWatters

I do not recommend testing to see if a spark plug lead will arc to the battery terminals. One day the battery will go boooooooom....

Last edited by a moderator: Sep 25, 2014
8. Oct 21, 2012

### CWatters

Easily explained.. It was running on the other three 3 cylinders.

Without a plug in cylinder 4 the piston may not draw fuel/air in through the inlet valve on the induction stroke. Even if you have a turbo pushing fuel/air in under pressure any that does get in won't be compressed but pumped out the spark plug hole. At best you get an ocasional near death experience in cylinder 4.

One day the little nail will fall out of the spark plug cap into the cylinder...

9. Oct 21, 2012

### fabianek

It runs rough on three cylinders untill i put that lead in that hole then it smoths out without sprk plug in and funny thing is theres no detonstion in that fourth cylinder..... So my question is what kind of spark we have inside and what outside coz its not the same????

10. Oct 22, 2012

### sophiecentaur

??? what do you mean by that? A spark is a spark - they differ only in the gas they flow through, the volts and the current. How have you seen what goes on "inside"?

PS what does "smoths out" mean?

11. Oct 22, 2012

### fabianek

ok i will try to explain ;)
the car runs rough on three cylinders but soon as i get that lead with jumping spark close to that forth cylinder it ,,smooths out means run as normal without the spark plug in .........
can u explain that ....????

what kind of spark is inside the cylinder with the spark plug in and what kind of spark is outside without spark plug just asking as it looks like it makes no difference to the running ability of the car :)

thats why i need to know what that spark is.....

Last edited: Oct 22, 2012
12. Oct 22, 2012

### HallsofIvy

Staff Emeritus
We don't know what you mean by "what kind of spark". A spark, anywhere, is electrons jumping from a place where there is an "excess" of electrons to a place where this not.

13. Oct 22, 2012

### sophiecentaur

What engine is it? It either uses pairs of spark plugs in series - so it actually needs a spark path through the unused lead for the partner cylinder to ignite. Or the ignition system is upset by failing to produce a spark on one output.

Failing that, there must be something you are not seeing or just not telling us. Unless you see flames bursting out through the open plug hole, there is no ignition in that cylinder.
I'm done with suggestions.

14. Oct 22, 2012

### fabianek

thats my point there is no ignition!!!! and car run as normal on 4 cylinders without spark plug in
all i want to know whats that spark that comes out of that coil thats it!!!

15. Oct 22, 2012

### sophiecentaur

No it doesn't. It may run 'smooth' but when you do it, there's no power demanded during your experiment. What engine is it?

16. Oct 22, 2012

### fabianek

yeah right 4500rpm and no power demand r u crazy ..:) anyways cheers for your replay looks like i need to keep trying on other forums ;)
all i want to is someone to explain it to me what that spark is in simple words

ps: engine 4 cylinder vauxhall 1800cc

17. Oct 22, 2012

### cjl

It may run smoothly, but you are definitely down on power, and that cylinder is not firing. I would be willing to bet that you could prove this if you put it on a dyno too.

18. Oct 22, 2012

### sophiecentaur

People believe what they want to believe - not hard evidence. If engines worked without a spark plug in one cylinder, they'd make them without one because it would be cheaper. The ignition circuit clearly needs a load on its output for the timing or even just the spark energy to be correct. That will be why the thing works better when there is a spark drawn from the disconnected lead. Without a plug in the hole, that cylinder consumes very little of the power that the other cylinders are producing.
Do we want a rational explanation or does it have to be the twilight zone?

19. Oct 22, 2012

### davenn

you have already been told that in the most simplest terms by HallsofIvy in post #12

it doesnt get any simpler than that

Dave