Not much info in the archives.

'87 notchie with the 2.8 V6. I have at least two cylinders who's plugs are arcing. New spark plugs correctly gapped with a wire feeler. I used dielectric grease and anti-sieze. These wires aren't original but I can't remember if I'm the one who put them on. This is the engine/tranny from my wrecked car that I just installed in my ex-Duke car. I do have the metal boots on. I recently wire-brushed them to look nicer but maybe I made them more conductive.

What are the consequenses of this problem? Does it cause poor fuel economy? Fire(o) hazzard?

What is the probable cause? Wires, plugs, metal heat shields, engine ground?

What is the best way to fix this? Wire sizes, brand, made-to-fit or cut-and-crimp?

Thanks,

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Jonathan
1987 Notchie - recovering from surgery
I'm not a mechanic but I play one in my garage - me
Power tends to corrupt, and absolute power corrupts absolutely. - Lord Acton
Those who hammer their guns into plows will plow for those who do not. - Thomas Jefferson

How do you know the plugs are arcing? Do you see a black insulator with streaks of white porcelain visible where the spark jumped, rather than to the ground strap?

I can see the little sparks in the dark.

Jonathan

Are they new wires?
Good wires should not arc. The insulation on the plug boots should not allow the wires to arc to the metal shields if the plugs are firing. The gap of the plug is much less than the wire to sheild distance so the arc should be at the plug unless the wires are not any good.

So I guess you mean on the outside, not the engine side of the plug...

Old wires with deteriorated insulation can do this. They don't have to be look deteriorated by eye for sparks to penetrate.

Leave your heat shields on; the less heat the boots see, the longer it will take before they deteriorate.

I'd go for a set of AC Delco wires if you're not picky about the fit.

If you are picky about how they look, there's nothing like custom-cut wires.

What will happen if I don't correct this?

Jonathan

You might notice misfiring eventually... the car will run like crap, especially in the rain.

You might cook other ignition system components, such as the coil, because of old wires.

It's normally more cost-effective to replace the wires soon, than to procrastinate and damage other parts, and end up having to replace the wires anyway.

if u can i'd try sticking some electrical tape over the cut or watevers there if u can,hey its worth a shot right?

What size wires do I need for a stock set-up? Do I need to be concerned with radio interference or is that a thing of the past? Any other factors/options to conscider?

Thanks,
Jonathan

7mm is fine.

As far as radio interference, get resistor core wire, not solid core.

Any typical stock style wire set from the auto parts store should be resistor core.

If you're buying custom cut-to-length wires, they're available in both types, so make sure you're getting resistor core.

Would I need special tools for the custom wire kit? I have t-strippers and Klein crimpers.

Jonathan

Just a tool to crimp the terminals onto the wires.

(What's a klein crimper?) whatever it is, you need a crimper with the correct dies.

Klein is a brand name.

Jonathan

And to add, you can always play around with the location of the #1 cylinder on the distributor cap. Doesn't have to be where the factory suggests.

By doing this, I was able to get a pretty decent layout without the distributor cap looking like a disorganized mess.

https://www.fiero.nl/forum/Forum2/HTML/104901.html

I looked on eBay for "spark plug crimper" and found what looks like a high-quality tool. I definately don't have one of those. My crimpers are just for your basic wire ends like bullet connectors and eye hole connectors, etc. The cool thing about the auction I found is I won't have to pay shipping. The store is just a few miles from my house! Sweet.

Thanks for the help,

------------------
Jonathan
1987 Notchie - recovering from surgery
I'm not a mechanic but I play one in my garage - me
Power tends to corrupt, and absolute power corrupts absolutely. - Lord Acton
Those who hammer their guns into plows will plow for those who do not. - Thomas Jefferson
The tree of liberty must be refreshed from time to time, with the blood of patriots and tyrants. - Thomas Jefferson

Press the metal boots in until they are snugly fit into the spark plug hole. That should stop the visible arcing. Whether or not your spark is still traveling into the block via the metal boot is still a question.

Charlie

Arcing is bad. If you see a spark on the outside, that means it's not occurring in the combustion chamber where obviously it's supposed to.

I noticed that I had arcing between several metal heat shields and the heads on my GT so I simply removed the heat shields off the spark plug boots. That eliminated the arcing, but I suspected the wires were less than prime. I finally got around to changing to a new set of 7mm wires and I reinstalled the metal heat shields as well. The arcing hasn't returned.

IF you are NOT experencing any missfire then you don't have a problem. What is happening is the metal is getting an inductive charge from the passing spark voltage. Take the metal sheilds off and if your engine works exactly the same, then put them back on and ignore it.

you should never see sparks. HV will creep thru a deteriorated boot. there is no tape that will stop that. I put a set of the bluemax wires on mine and scrapped the metal altogether. the make your own wire sets that I have gotten come with a crimp block set to put the dist end on. That is what I use on my boat with the upgraded hei system, and never had any problem with them, but I do feel the new bluemax wires are not as good as the ones from 10-15 years ago. (so what else is new... lol )

I haven't noticed any performance problems. My economy isn't great but I haven't been able to run this engine that much since the swap. I am having a little bit of a rumbly, poppy, backfire-ish noise on decelleration. Even that doesn't happen all the time. I guess it is hard for me to judge the performance since I'm coming from an L4 that wasn't top notch to a V6 that I haven't used for over 2 years. I can't really say I know what it is supposed to be doing or not doing.

Jonathan

[This message has been edited by Boostdreamer (edited 03-27-2010).]

Well you can always take them off like others have done. My understanding is that they are supposed to help protect the boot from the extra heat. (but when I think about it I would thing that would actually make them retain the heat) Worst thing from not having them on is accelerated spark plug boot deterioration.

Assuming its only induction the electrical energy does not travel through a crack in the boot in a spark fashion, but electromagnetically to the metal. If it is traveling as a spark then you would be getting misfires on those plugs.

Energy is energy and it doesn't matter how it gets to the metal shell, some of it is lost from going to the plug. You will get a 'hotter' spark, but minutely. The engineers at GM surely considered this when they designed it this way and they didn't feel it was a problem.

Mine are on




Sometime I need to put a plastic shell on the temperature sender. Rodney sells them I know.

I cut down my replacement spark plug wires to the right lenght to give them a stock look. I just crimped them with the pliers I have here.

A burbling noise on deceleration is normal.

Lots of cars do it, especially sporty-type cars with open exhausts.

AC/Delco wires are $50. That seems a bit pricey to me for wires are the length that someone else wanted and colored either black or gray. I might have done it if they had been red or yellow. I guess I'll go buy a custom crimp kit. The speed shop where I bought the spark plug wire crimpers had a set for $38.

Jonathan

I finally bought spark plug wires. I made up my mind that I wanted yellow so I got Accel 8mm Super Stock Wires. I am waiting for the car to cool down and for supper to be over before I start the trade.

In other news, I had my exhaust worked on today. They determined that the joint where the Y meets the cat was weak because the flanges had deteriorated and were no longer holding the two pieces together with sufficient pressure. They cut the flanges off both pieces and welded in a straight section.

The car is MUCH quieter now. It is amazing how much noise was escaping through that joint. Also, my rumbly, popping, back-fire-ish noise is now COMPLETELY GONE!!! I can actually drive and talk on my cell phone and hear what the other person is saying!

The wires were $38 from O'Rielly and the welding was $38 also. I'll post again after I get the new wires on and get a chance to drive it. May be tonight or tomorrow.

Jonathan

As a follow-up, you should measure the resistance of each of the old wires, end-to-end individually with an ohmmeter if you have one, and post the results. A good spark plug wire measures about 10,000 ohms per foot of wire. That means that none of your wires should measure more than about 30K ohms. I'd be willing to bet that your old wires are up in the 50K-70K ohm range. The resistance of the wire increases with age and heat and that's what the main cause of arcing is... the spark energy (about 40,000 - 50,000 volts) finds the path of least resistance to ground and arcs either through the spark plug if the wires are good, or if the wire presents too much resistance, it will arc through the insulation rather than continue down the wire.

I measured the resistance of my old and new wires. The new wires actually read HIGHER resistance by roughly twice as much. The old wires are showing 5-7K ohms and the new ones are like 14K. Anyway, I'm not seeing anymore arcing and the performance is good. I am not using the metal boot protectors. Mileage also seems to be good after about 80 miles on the new wires.

One thing I didn't expect was that new plug wires could cure a clutch problem. I thought my clutch was slipping ( and maybe it is) but the hesitation I did have is minimized greatly. I'm not in any big hurry to change my clutch now. So glad because I really didn't want to do it in these cold temperatures.

Jonathan

So put the metal boots back on to see if you get inductive arcing. I really say you will. And no, it's not the actual spark jumping to ground. It's just an inducted voltage in the metal jumping to ground.

quote Originally posted by phonedawgz: What is happening is the metal is getting an inductive charge from the passing spark voltage.

quote Originally posted by phonedawgz: So put the metal boots back on to see if you get inductive arcing. I really say you will. And no, it's not the actual spark jumping to ground. It's just an inducted voltage in the metal jumping to ground.

Would you mind explaining this "inductive arcing" principle? I've never heard of it in a spark plug wire.

From what I recall in electrical theory, current flowing through a primary wire creates an electromagnetic field around the wire according to the right hand rule. That EMF can induce a current in a secondary wire running along the same axis as the primary wire, but the energy isn't transferred through arcing. Arcing between a current carrying wire and another object occurs simply because there is insufficient insulation to prevent the electrical energy from taking the intended route, ie, the spark plug gap. You can have arcing along the plug wire and at the spark plug tip simultaneously, so just because you see arcing on the outside, doesn't mean you're going to get a misfire. The spark at the plug tip will be weaker though since some of the energy was lost through the arcing.

Once the plug fires and the pulse of current flows, that will create the electromagnetic field. The collapse of that field will cause an induced voltage in the secondary (the shield) That induced voltage will cause a spark to ground if the gap is small enough.

If you scan posts in the past there have been quite a number of reports of these sparks, visible in the dark. One person 'solved' the problem by having the sheild touch the block. Many others have 'solved' the problem by removing the sheilds.

Many past reports have stated that the person sees the spark on multiple or all cylinders but the engine appears to be operating fine.

The sheild to ground sparking, or even the grounded sheilds don't cause any perceived operational issues. That shows that the sparking is caused by a secondary voltage since if the primary spark voltage was grounded that cylinder would surely miss.

This same princible can be seen when you grab the top of the distributor to time your engine. You feel a shock in your hand. That shock is an induced shock from wires to your nerves.

Does the sheild 'drain' some of the spark energy? I don't think to any real degree. 1 - GM engineers designed them as part of the stock engine and they would not have designed something that degraded the spark substantially. 2 - The sheild spark comes from the collapse of the magnetic field - which means it comes from the end of the spark pulse.

That's just how I see it. That's why I would like someone with brand new plug wires who has seen the sparking before to confirm they still have it. Of course if the problem is degraded insulation, and the spark is actually traveling from the wire core, to the sheild to ground, that will for sure cause a misfire on that cylinder.

I thought my new plug wire boots would be too skinny to use the heat shields but they do fit in there snugly. They just don't have the little ribs to make it a perfect match. I might try to put them on again on the rear plugs to observe some night. It it too freaking cold to be messing around out there for fun right now.

By the way, thanks again to everyone who participated in my thread! I always appreciate the help. As you can see from the difference in my beginning and later post dates, I do try to finish up what I start for the sake of other members who might search the archives later. I hope this will be helpful to somebody.

Jonathan

Electricity always follows the path of least resistance, that is what was causing the arching you saw. It's also known as a high voltage leak.
Here is an article that talks about this. It WILL affect how your engine runs and sometimes can even be heard when you are listening to the car's radio.
http://autorepair.about.com.../qt/plugwire_chk.htm

quote An arcing plug wire can cause a weak spark or no spark at all in the cylinder with the bad wire. This makes your car run rough and can affect your gas mileage. It can also cause unburned fuel to pass into the exhaust system where it can harm your catalytic convertor. There have even been stories that involve both a fuel leak and an arcing plug wire, resulting in a fire! It can happen.

Here is another article on spark plug wires.
http://www.magnecor.com/magnecor1/main.htm
and one more.
http://www.custompistols.co...ticles/sparkplug.htm

Replacing the spark plug wires was the correct solution, unless you got a cheap pair, which could fail almost immediately.

[This message has been edited by avengador1 (edited 01-14-2011).]

quote Originally posted by phonedawgz: Once the plug fires and the pulse of current flows, that will create the electromagnetic field. The collapse of that field will cause an induced voltage in the secondary (the shield) That induced voltage will cause a spark to ground if the gap is small enough. The sheild to ground sparking [...] don't cause any perceived operational issues.

You seem to be saying the arc jumps from an induced voltage in the heat shield to ground. The problem with this is that the heat shields are grounded through direct contact with the cylinder heads.

quote Originally posted by phonedawgz: This same princible can be seen when you grab the top of the distributor to time your engine. You feel a shock in your hand. That shock is an induced shock from wires to your nerves.

I beg to differ on this point. If your theory of induction arcing were true in this case, then new wires would shock people just as easily as old ones since EMF isn't dampened by silicone insulation. Therefore the amount of EMF would be the same in either case, and so too would the "induced shock". The truth is, you can grab new plug wires without being shocked. When you do feel a shock, it's because of voltage leakage, not induction. If you ever feel a shock to your hand when grabbing a spark plug wire (or the distributor), it's time to change the wires or narrow the gap on your plugs. The high voltage is taking a short cut through the insulation and into your body because it's the path of least resistance. It also means it'll do the same thing if the wire rests on any nearby grounded metal.

quote Originally posted by phonedawgz: Of course if the problem is degraded insulation, and the spark is actually traveling from the wire core, to the sheild to ground, that will for sure cause a misfire on that cylinder.

This may be true in some cases, but all. As the resistance of plug wires increases over time, there will be a period where the resistance to jump the spark plug gap will be similar to the resistance of jumping through the insulation to another ground. During that time, a weaker spark will jump in both places resulting in both, an arc outside the wire, and an arc at the end of the plug. This is the same reason why lightening doesn't take only one path to ground but forks out in several paths.

quote Originally posted by Boostdreamer: I measured the resistance of my old and new wires. The new wires actually read HIGHER resistance by roughly twice as much. The old wires are showing 5-7K ohms and the new ones are like 14K. Anyway, I'm not seeing anymore arcing and the performance is good without the metal plug shields. Jonathan

I was expecting to find the exact opposite. It made sense that the resistance would be higer in old wires. But like I said, I may have been the one who put those wires on. If so, the core of the wires should have been fine but the insulation around them could have been brittle from being too close to the headers since all those wires were too long. Any other thoughts on the unexpected resistance meausrements?

Jonathan

quote Originally posted by avengador1: Electricity always follows the path of least resistance, that is what was causing the arching you saw. It's also known as a high voltage leak. Here is an article that talks about this. It WILL affect how your engine runs and sometimes can even be heard when you are listening to the car's radio. http://autorepair.about.com.../qt/plugwire_chk.htm Here is another article on spark plug wires. http://www.magnecor.com/magnecor1/main.htm and one more. http://www.custompistols.co...ticles/sparkplug.htm Replacing the spark plug wires was the correct solution, unless you got a cheap pair, which could fail almost immediately.

This discussion is about an inducted voltage on the metal spark plug shell, not a direct high voltage spark caused by degraded insulation. Boostdreamer said he had two spark plug wires doing this but didn't notice any performance differences. If he had two plug wires that were shorting to ground, I'm sure he would have noticed it.

quote Originally posted by phonedawgz: I'm not the one saying it, Boostdreamer said he is seeing these sparks between the shells and ground.

Re-read the thread and you'll see he never states where the arcing is taking place.

quote Originally posted by phonedawgz: I agree that new wires would act exactly like old wires, just as long as what we are talking about isn't a direct spark, but an induced spark.

So then you agree that you can't get an "induced shock" by holding a wire? Because new wires don't shock you, only old ones, and the reason old ones shock you is because of voltage leakage. Agreed?

quote Originally posted by phonedawgz: Grab the top of your distributor like you are setting the timing and have your other hand touching ground.

People (and I) do this all the time without getting shocked. How else can you turn the Fiero distributor to set the timing? The only accesible part is the top. If you are getting shocked, do you believe it is because of induction? Because I thought you had agreed wires can't shock you through induction as stated above.

quote Originally posted by phonedawgz: Well again see if you can get a 'dual spark' to ground and keep your lawn mower running.

Because you are not able to, doesn't mean it can't be done. An electrical current will follow more than one path if the conditions are right.

quote Originally posted by Bloozberry: Re-read the thread and you'll see he never states where the arcing is taking place.

Yeah the title says sparking at the spark plug boots and then we go into a discussion of sparking from the metal shell to the engine. Jonathon called them "little sparks" Then the discussion went into the sparks being between the shells and the block. Jonathon was part of the conversation. Perhaps it's not shell to engine and boostdreamer just didn't bother to correct us. Can you help here boostdreamer where you saw the sparking? Plug shell to ground or elsewhere?

quote So then you agree that you can't get an "induced shock" by holding a wire? Because new wires don't shock you, only old ones, and the reason old ones shock you is because of voltage leakage. Agreed?

Nope - What I agreed to is in my box.

quote People (and I) do this all the time without getting shocked. How else can you turn the Fiero distributor to set the timing? The only accesible part is the top. If you are getting shocked, do you believe it is because of induction? Because I thought you had agreed wires can't shock you through induction as stated above.

You can turn it by grabbing the sides.
Yes
No I didn't agree wires can't shock you through induction. The idea that wires can shock you through induction is the point of my posts. New wires will give you induction shocks just the same as old wires.

quote Because you are not able to, doesn't mean it can't be done. An electrical current will follow more than one path if the conditions are right.

I agree with the first and second sentence. I also can tell you that whenever I've seen a true high voltage secondary spark to ground outside the engine (bad wires or cap or cracked plug) that caused the cylinder to not fire. Again if you want to prove that you can establish two spark paths to ground go ahead. Everything I have been taught on high voltage ignition states once the voltage is high enough to ionize a path to ground, that is the sole path to ground that spark will take. I have never seen it otherwise.

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So I have just tried it on my 2.8. I took my 12v test light and grounded one end. I held the sharp probe tip up to the shell and moved till I touched the shell. Just before touching the shell I get a small blue static looking spark. The spark doesn't affect engine operation. Idle speed doesn't drop. And I can get the spark to repeat if I hold the test light just off of the shell.

So if not induced, how do you propose that voltage gets on the shell? If it were a breakdown of insulation, I would get a much larger spark and the cylinder would misfire.

[This message has been edited by phonedawgz (edited 01-14-2011).]

If you want me to respond, you're going to have to edit your last post because your answers are jumbled and hard to follow.

quote Originally posted by Bloozberry: If you want me to respond, you're going to have to edit your last post because your answers are jumbled and hard to follow.

I see.