Spark plug wire arcing, is this normal?
#1
02-07-2010, 08:07 AM
Spark plug wire arcing, is this normal?
my rear spark plug wire arcs when I touch it. Shocks the shizit out of me too. I can touch the front one without a problem. What causes this? Should I replace the back wire to fix the issiue or both wires? any info would be greatly appreciated. thanks. Any wires better than stock?
#2
02-07-2010, 08:11 AM
Road Warrior
#7
02-07-2010, 11:40 AM
my rear spark plug wire arcs when I touch it. Shocks the shizit out of me too. I can touch the front one without a problem. What causes this? Should I replace the back wire to fix the issiue or both wires? any info would be greatly appreciated. thanks. Any wires better than stock?
The way it works is ignition spark energy will take the path of least resistance to ground. By design, the spark plug wires should provide enuff insulation to contain the high pressure voltage and not leak even when wet, forcing the voltage to reach ground only by jumping the gap offer by the spark plug tip. But age and dirt, and fouled plugs often tend to offer that high voltage an easier path to ground than thru the spark plug gap.
You gotta remember that the spark plug has a gap where the ignition voltage is expected to jump that gap and in doing so generate a spark that is intended to ignite the fuel/air mix-that same gap generates a lot of resistance....So the whole system is based on high resistance which can only be overcome by high voltage-and that resistance is supposed to be reserved to be overcome only at the spark plug gap....If ignition voltage/pressure ain't contained and it can leak out anywhere besides jumping that high resistance gap at the spark plug, then you gotta fix that.
Does that mean your spark plug wires need to be changed? NO
What it means is you need to first make sure the plug is cleaned and gapped correctly. Too big a gap will invite the voltage to look for a path to ground external to the insulation offered by the conductor....So will a loose or dirty insulator boot at either the plug or the coil. Usually plugs foul and even tho it seems the gap closes as observed by the fouling, the fouling causes a higher resistance than experienced with a properly gapped and clean plug.
Before you spend money, first pull and examine your plugs and plug wires....clean and regap the plugs, also wipe the wires clean and use proper dielectric lube on their boots where they plug into the coil and plug, then make certain they are inserted fully.......Also clean the exterior ceramic portion portion of the plug and look closely for carbon tracking...Remove any possibility of low resistance to ground other than the high resistance offered by a properly gapped plug and a clean and electrically sealed wire assembly......Of course, gently bend the wires and look to see if they have cracked even the slightest....If after that you still feel a tingle, then replace your wires with new and/or high performance wires.
You should look at your plug wires like they are high pressure hoses designed to contain super high pressure fluids, because electricity is just like any fluid where it will leak at the weakest point if allowed.
Last edited by oinker02; 02-07-2010 at 12:43 PM.
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#8
02-07-2010, 12:33 PM
Heh, heh....that super high voltage you got going on with the ignition will sure straighten your hair, huh?
The way it works is ignition spark energy will take the path of least resistance. By design, the spark plug wires should provide enuff insulation to contain the high pressure voltage and not leak even when wet forcing the voltage to reach ground only by jumping the gap offer by the spark plug tip. But age and dirt, and fouled plugs often tend to offer that high voltage an easier path to ground than thru the spark plug gap.
You gotta remember that the spark plug has a gap where the ignition voltage is expected to jump that gap and in doing so generate a spark that is intended to ignite the fuel/air mix-that same gap generates a lot of resistance....So the whole system is based on high resistance-and that resistance is supposed to be reserved to be exploited only at the spark plug gap....If ignition voltage ain't contained and it can leak out anywhere besides jumping that high resistance gap at the spark plug, then you gotta fix that.
Does that mean your spark plug wires need to be changed? NO
What it means is you need to first make sure the plug is cleaned and gapped correctly. Too big a gap will invite the voltage to look for a path to ground external to the insulation offered by the conductor....So will a loose or dirty insulator boot at either the plug or the coil. Usually plugs foul and even tho it seems the gap closes as observed by the fouling, the fouling causes a higher resistance than experienced with a properly gapped and clean plug.
Before you spend money, first pull and examine your plugs and plug wires....clean and regap the plugs, also wipe the wires clean and use proper dielectric lube on their boots where they plug into the coil and plug, then make certain they are inserted fully.......Also clean the exterior ceramic portion portion of the plug and look closely for carbon tracking...Remove any possibility of low resistance to ground other than the high resistance offered by a properly gapped plug and a clean and electrically sealed wire assembly......Of course, gently bend the wires and look to see if they have cracked even the slightest....If after that you still feel a tingle, then replace your wires with new and/or high performance wires.
You should look at your plug wires like they are high pressure hoses designed to contain super high pressure fluids, because electricity is just like any fluid where it will leak at the weakest point if allowed.
The way it works is ignition spark energy will take the path of least resistance. By design, the spark plug wires should provide enuff insulation to contain the high pressure voltage and not leak even when wet forcing the voltage to reach ground only by jumping the gap offer by the spark plug tip. But age and dirt, and fouled plugs often tend to offer that high voltage an easier path to ground than thru the spark plug gap.
You gotta remember that the spark plug has a gap where the ignition voltage is expected to jump that gap and in doing so generate a spark that is intended to ignite the fuel/air mix-that same gap generates a lot of resistance....So the whole system is based on high resistance-and that resistance is supposed to be reserved to be exploited only at the spark plug gap....If ignition voltage ain't contained and it can leak out anywhere besides jumping that high resistance gap at the spark plug, then you gotta fix that.
Does that mean your spark plug wires need to be changed? NO
What it means is you need to first make sure the plug is cleaned and gapped correctly. Too big a gap will invite the voltage to look for a path to ground external to the insulation offered by the conductor....So will a loose or dirty insulator boot at either the plug or the coil. Usually plugs foul and even tho it seems the gap closes as observed by the fouling, the fouling causes a higher resistance than experienced with a properly gapped and clean plug.
Before you spend money, first pull and examine your plugs and plug wires....clean and regap the plugs, also wipe the wires clean and use proper dielectric lube on their boots where they plug into the coil and plug, then make certain they are inserted fully.......Also clean the exterior ceramic portion portion of the plug and look closely for carbon tracking...Remove any possibility of low resistance to ground other than the high resistance offered by a properly gapped plug and a clean and electrically sealed wire assembly......Of course, gently bend the wires and look to see if they have cracked even the slightest....If after that you still feel a tingle, then replace your wires with new and/or high performance wires.
You should look at your plug wires like they are high pressure hoses designed to contain super high pressure fluids, because electricity is just like any fluid where it will leak at the weakest point if allowed.
I'm sure there will now be peeps chiming in proclaiming you should spend $$$ buying NGK, Denso, Iridiums, etc, but why? Your just diagnosing a problem right? The Champions work just fine if changed as MoCo recommends every 10K miles.
#9
02-07-2010, 06:33 PM
#10
02-07-2010, 06:44 PM
Stock Harley wires are junk, I bet they don't pay more than $1 a set. I always change the stock wires to MagNaCores. Best wire money can buy and not expensive.
Whatever you replace them with just don't buy Sceamin Beagles, they are the same cheapo wire with a differant cover.
Whatever you replace them with just don't buy Sceamin Beagles, they are the same cheapo wire with a differant cover.