|06-20-2013 09:32 PM|
|billybedford||jk'n I want to party with you.|
|06-20-2013 09:16 PM|
|flflash||The proper use of that capacitor is to carefully charge it then set it on the bench and wait to see who picks it up.....the 70's where Fun Times|
|06-20-2013 09:00 PM|
|06-20-2013 08:43 PM|
|06-20-2013 08:37 PM|
|06-20-2013 08:29 PM|
|Ibuildembig||Lol this reminds me of college. The professor would preach over and over about a lab only to have it blow up when we built it. Take out a part, change a few wires and it was good as gold. Life lesson on just because the theory supports it, Murphy's law sometimes overrules. On to other things.....later|
|06-20-2013 08:22 PM|
|06-20-2013 08:21 PM|
|06-20-2013 08:13 PM|
|harleydragon||the condensor ( capacitor ) was originally on there to help cut down on radio interference..It was of little good then but with todays much better plug wires,better resister spark plugs,much better radios and antennas it is not needed..most vehicles from the 60's had them originally|
|06-20-2013 08:04 PM|
|Ibuildembig||Like I said, your all alone in the jeep world of leaving well enough alone and stock is fine. Your argument can be made regarding any and every part on a jeep. Here's a thought you may not have addressed: since the op already said his new part only had two wires and not three, is it possible that they figured out its not needed? For if it was, wouldn't they have made such provision for it to be connected? I've never seen a manufacturer instruct a consumer to butt splice something like that.|
|06-20-2013 07:26 PM|
I offered standard scientific explanations as my proof which ARE proven facts based on circuit design. What we are really disagreeing on is semantics.
My advice is simple. Leave it in there if it was designed that way and there is no proof via a change order from Jeep (Chrysler) via a service bulletin to do otherwise. That is considered sound practice. If you install a modified ignition system I would say follow the recommendations of the maker of that system. A new wiring harness does not qualify as installing a new ignition system. I would not be able to have this discussion with you if the OP had said that he was installing a new and improved ignition system.
Regarding your practice, it may be a case of just dumb luck that nothing bad has happened in your case. I would call it anecdotal evidence. That is different from good practice or re-engineering. It is also not possible for me to know if you haven't had a change from the original ignition system which might explain your good results. I go back to my original statement that I would do this if the ignition system is stock or a stock replacement.
This is always my advice on stock equipment. If you make modifications by using aftermarket parts then my advice would have been different and would always start with following the manufacturers recommendations.
If you were an engineer and have re-engineered your system then that is good for you. Selling your idea to others is all well and good as long as you are prepared to deal with any repercussions that may arise. Most of us are not capable of re-engineering our own systems that is why we purchase aftermarket kits built for a specific purpose. I don't recommend these unless there is a substantial benefit over the stock parts. If your vehicle is stock try to keep it that way if all you want is a good repair.
|06-20-2013 06:39 PM|
|06-20-2013 03:06 PM|
|Ibuildembig||LOL I'm not looking to agree or change your mind. I simply stated its not needed and provided proof and personal experience|
|06-20-2013 12:12 PM|
|jk'n||OK if you are looking for agreement I'll try to come up with a scenario where we may agree. You are replacing the ignition module and the directions that comes with the new module claims that the circuit has been re-designed from the original and no longer needs the external capacitor.....BINGO.....we would agree.....throw that cap out. Not what happened here that I'm made aware of by the OP. The OP has replaced only wires, not the whole module.|
|06-20-2013 12:06 PM|
|jk'n||I'd have to read up on those modifications. I would only speak to an unmodified ignition system. Go with what was designed is my advice. What you are referring to is a significant modification and I would defer to the instructions that came with the mods. You appear to be splitting hairs to try and get me to agree with you. It is apples and oranges.|
|06-20-2013 08:56 AM|
I'd say running 28 years without one with no issues should speak for itself. I grew up with 12v electronics, hold a bachelors in the discipline, and work in the industry everyday.
Food for thought: if a guy did a nutter bypass and used an hei dizzy, is the cap still necessary in your opinion?
|06-20-2013 08:01 AM|
I have been thinking about this one for a while.
Putting a new wiring harness in is not a reason to change a circuit from it's original configuration. If they omitted something on the harness, it just means that the manufacturer did not configure it in its original configuration.
In post number six I gave the somewhat layman's explanation of the capacitor across active device that interrupts current to the coil. I don't really need to see the remainder of the diagram. Coil circuits perform essentially the same whether there are points generating the spark or some kind of electronic circuitry that has taken the place of the points. I have devoted the first part of my life in the study of electronics and know quite a lot about it. In a point system, surely, the capacitor across the points will cause noise in the radio if it does not function because it has suddenly become defective. But what else will happen? Because of the inductive kick caused by the opening of the points is no longer being limited, there will be large voltage spikes across the points as they open and lots of arcing and sparking. This will cause the points to wear prematurely, become pitted and cause high resistance where there should be low resistance. The overall performance of the coil will decrease because of the high resistance. Replacing the capacitor and a new set of points will restore the circuit to functioning normally. In an electronic spark system as I said above, there is an active device that does the same function as the points. The capacitor is across the active device. I can guess this not even having to look at the diagram because it would serve the same purpose. Removing the capacitor may cause noise in the radio but more importantly, the voltage across the active device will now rise significantly and stress the junctions in the active device. The result of removing the capacitor may not be immediately apparent. The active device malfunctioning may take some time to occur. You may not even realize what the cause and effect was by the time that the active device craps out. If it does go, it means replacing the whole unit as repair of the single bad component is generally not possible. This is the long explanation about why the capacitor should remain in the circuit. It is also the scientific explanation. It is why I would include the capacitor in the rewiring of the circuit if it were my jeep.
|06-18-2013 12:30 PM|
|jk'n||Or try to keep it as it were.....|
|06-18-2013 09:44 AM|
|Ibuildembig||But the OP was asking the question about his new harness having 1 less wire that went to said cap....in this instance he has a choice to have to mod something to keep it or just delete it alltogether.|
|06-18-2013 07:45 AM|
|jk'n||No, you are reading what I said wrong. I'm saying that unless there is a compelling reason to change it from it's original configuration then leave it that way. Especially if there is nothing wrong with the original design.|
|06-18-2013 12:02 AM|
|Ibuildembig||Your into the wrong kinda vehicle to keep things stock lol. I can tell you from over 25 years in the industry it works fine without it.|
|06-17-2013 10:55 PM|
|jk'n||Funny thing about how things get named. Yes, the capacitor may function to reduce noise in the radio and that is the most noticeable effect. I can't see the remainder of the circuit where the capacitor is in the circuit. If it functions in the same position as in a point system but across the active device which interrupts the circuit to the primary of the coil then it also has the same effect as in a point system which is to limit the voltage across the active device. Active devices when in overvoltage situations become shorted and non functional. When I repair a system, unless there is reason to alter it, I put it back to its original configuration. If this capacitor has created problems over the years and there has been a service bulletin about it that says it is not necessary, then surely remove it. Absent such credible evidence, I would restore the circuit back to its original configuration.|
|06-17-2013 10:23 PM|
Here's a page from my 70's model truck wiring manual. It plainly states "radio interference capacitor". This is used because they "felt" it could be needed in removing any noise from the less than stellar factory radios which had poor sensitivity and even poorer selectivity. Since Jeep used an all Ford ignition system in the early YJ's, this also applies to them as well.
|06-17-2013 07:38 AM|
|jk'n||^^ I would consider that gospel coming from the circuit diagram. If it was there, and a PO didn't put it there then it must have been there from stock. They don't throw extra parts in at the factory for the hell of it.|
|06-16-2013 11:26 PM|
|Ibuildembig||It's not needed, same ignition as a 70s model pickup.|
|06-16-2013 04:27 AM|
|jk'n||Interesting. Even though the coil is excited by a system that is more in the realm of electronics rather than a switch the function of the capacitor is the same. The circuitry of the coil is closed by a switch (points) or by an active device (typically a transistor) and current flows through the primary of the coil. When a spark is called for the current flowing in the primary of the coil is interrupted by the opening of the points or turning the transistor off. Because in a coil the collapsing magnetic field will generate a large voltage across both the primary and secondary coils this is what produces the 30,000 volts or so that generates the spark however in the primary circuit that large voltage spike will cause noise in the radio and could destroy the transistor that controls the circuit because of over-voltage across it. The capacitor limits the voltage across the coil primary. So without that capacitor it may cause more problems than just the noise in the radio.|
|06-14-2013 08:09 PM|
|06-13-2013 10:21 PM|
|jk'n||I was suspecting that you were possibly referring to the capacitor. I don't know what system your jeep uses but in a point ignition system the capacitor prevents pitting on the points because it limits the effect of inductive "kick" that is created by the opening points. By effect, it also suppresses the noise created by the arcing of the points that would be heard by the radio as static. Suffice it to say that if the capacitor is part of your ignition system, it was meant to be there and there will likely be consequences if it isn't there beyond the noise in the radio.|
|06-13-2013 05:50 PM|
|06-12-2013 08:59 PM|
|jk'n||Picture of little cylinder thing?|
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