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Bad Spark Plug Wires? by TWright
Started on: 01-01-2013 09:09 AM
Replies: 16 (499 views)
Last post by: rogergarrison on 10-07-2014 02:31 PM
TWright
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Report this Post01-01-2013 09:09 AM Click Here to See the Profile for TWrightClick Here to Email TWrightSend a Private Message to TWrightEdit/Delete MessageReply w/QuoteDirect Link to This Post
I recently purchased a 1987 GT and noticed something unusual: At idle, I can see arcing between the metal spark plug shields and the head! I don't know how old the wires are, but they look almost new.

I repositioned the shields (pulled them slightly away from the head) and the arcing stopped. (Who knows what the front ones are doing, they're kind of buried in there.)

Is this arcing normal, or should I go buy some new spark plug wires?
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TONY_C
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Report this Post01-01-2013 10:00 AM Click Here to See the Profile for TONY_CSend a Private Message to TONY_CEdit/Delete MessageReply w/QuoteDirect Link to This Post
Arcing from spark plug wires is not normal and is never good. Sounds like you need a new set, looks can be deceiving.
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jetman
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Report this Post01-01-2013 08:26 PM Click Here to See the Profile for jetmanClick Here to visit jetman's HomePageClick Here to Email jetmanSend a Private Message to jetmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Try applying a liberal coat of dielectric grease to the spark plug boots, see what your results are. I actually removed the shields from my V-6, that's your call though. On the firewall side, you can use a trouble mirror, after dark, see what's happening back there. The spark plug wires may be "el-cheapo", you know, just to sell the car.

The big question is what condition the firewall side plugs are in, as you may know, most folks tend to ignore them since thay're so hard to get at, you can pull a plug wire and get a visual on them, trouble mirror, get an idea of what you're up against.
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TWright
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Report this Post01-01-2013 08:56 PM Click Here to See the Profile for TWrightClick Here to Email TWrightSend a Private Message to TWrightEdit/Delete MessageReply w/QuoteDirect Link to This Post
All of the plugs were just changed by me, so I know they are good. The wires on the other hand....
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TWright
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Report this Post02-17-2013 04:17 PM Click Here to See the Profile for TWrightClick Here to Email TWrightSend a Private Message to TWrightEdit/Delete MessageReply w/QuoteDirect Link to This Post
OK. I have now changed the Distributor Cap, Rotor, Wires and Spark Plugs. The wires are brand new Bosch and the arcing still continues. Any ideas?

[This message has been edited by TWright (edited 02-17-2013).]

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Lou6t4gto
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Report this Post02-19-2013 02:12 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
If the spark is jumping from the shield to the engine, the spark IS NOT jumping the PLUG ! I've been running NO Shields for 5 years ,no problems.
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donuteater306
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Report this Post10-04-2014 01:26 AM Click Here to See the Profile for donuteater306Click Here to Email donuteater306Send a Private Message to donuteater306Edit/Delete MessageReply w/QuoteDirect Link to This Post
Having this same problem. Searched and found this thread. Did you ever find a solution? Mine has new plugs, cap, rotor, wires. Still arcing.
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olejoedad
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Report this Post10-04-2014 08:21 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Did you coat the inside of the boot (and the porcelin on the plug) with dielectric grease? Do you have the paper shields inside the metal heat shields? Are the heat shields pulled up on the boot (away from the tip of the boot) as far as possible?
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Lou6t4gto
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Report this Post10-04-2014 01:12 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
the last couple of years, I've found you need to CHECK every wire with an OHM meter right out of the box. I bought 2 sets of autolite plug wires and both times found 2 wires were bad, Brand new ! you cannot take for granted because something is new that it is actually any good.
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Gall757
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Report this Post10-04-2014 02:00 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Lou6t4gto:

you cannot take for granted because something is new that it is actually any good.


Repeated for emphasis...20 years ago it was pretty much true, but not any more.
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Patrick
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Report this Post10-04-2014 03:13 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by donuteater306:

Having this same problem. Searched and found this thread. Did you ever find a solution? Mine has new plugs, cap, rotor, wires. Still arcing.


Years ago I wondered about this myself when I got my first V6 Fiero, and I read in these forums that this is... normal.

Keep in mind that I'm not talking about faulty plug wires that are actually shorting to ground. Arcing from the metal shields to the heads is caused by electrical induction. (I hope I'm using the correct term.) The arcing you see is not the same spark that is going to your plugs (but it's caused by that same charge).

[This message has been edited by Patrick (edited 10-04-2014).]

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donuteater306
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Report this Post10-05-2014 11:27 PM Click Here to See the Profile for donuteater306Click Here to Email donuteater306Send a Private Message to donuteater306Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hey thanks for the replies. I did use dialectric grease on the boot, but not on the plug...other than what transferred from the boot. My shields do have the paper inside and I do have them pulled as far up as possible. The wires are STI brand.

I wrapped a small amount of electrical tape around the end of the shield and that seems to have stopped it. But I doubt that with the heat, the tape is going to last. Bugs me because, from what ittle I understand about electricity... I'm assuming that if the spark is leaking out of the boot, that I'm not getting full energy at the plug.
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Patrick
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Report this Post10-06-2014 12:21 AM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by donuteater306:

I'm assuming that if the spark is leaking out of the boot, that I'm not getting full energy at the plug.


Ummm... did you read my post?
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donuteater306
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Report this Post10-06-2014 08:21 PM Click Here to See the Profile for donuteater306Click Here to Email donuteater306Send a Private Message to donuteater306Edit/Delete MessageReply w/QuoteDirect Link to This Post
I just did, i'm sorry Pat. But if it's normal, why didn't my old wires do it?
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Patrick
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Report this Post10-07-2014 01:20 AM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by donuteater306:

But if it's normal, why didn't my old wires do it?


I'm just guessing, but perhaps the resistance was higher in your old wires, and this resulted in less electrical induction taking place.

The point is, the arcing you see jumping from the metal shields to the heads is not the voltage from the coil which is heading for the plugs. If it was, NONE of the voltage would be reaching the plugs, and none of those cylinders would be firing. Electricity takes the path of least resistance. The arcing is a by-product of the voltage going through the wires and metal shields in transit to the plugs.

I suspect that this arcing is a whole lot more common than most people realize. I didn't notice it until I looked at my engine running in pitch black darkness. I was pretty surprised at what I saw (and alarmed!), but found out eventually that it was nothing to worry about.

[This message has been edited by Patrick (edited 10-07-2014).]

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sardonyx247
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Report this Post10-07-2014 01:23 AM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
I always pull the sheilds and toss them. I have yet to see a melted boot from running without the sheilds.

Some wires just suck, well most of them really. The cheap ones from autozone WILL leak spark right out of the box brand new.
I go for the low ohm wires, sooo much better than the resistance core wires, and without any radio noise. Low ohm wires rarely will leak spark. IE less than 200ohms a foot, compared to 6,000 to 8,000 ohms per foot. Taylor makes some good wires.
The only reason they made the wires so high ohms is to suppress radio noise, Jacobs came out with the design for the low ohms and zero radio noise, win win.


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rogergarrison
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Report this Post10-07-2014 02:31 PM Click Here to See the Profile for rogergarrisonClick Here to Email rogergarrisonSend a Private Message to rogergarrisonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Im another one who just tosses the shields. Never had a problem.
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