Is it normal for spark plug cables to shock you when engine is running?? (please read explanation inside)

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Mr. Bunny - 21 Sep 2006 21:53 GMT

I've never really noticed this on other vehicles, so I'm not entirely sure
if this is normal or not, BUT:

On our '92 Tempo w. 175,000 km on it, I was changing the spark plugs and
then fired up the car to make sure it ran ok. Then, before closing the hood
I wanted to double-check if the cables were seated properly. So while the
engine was still running, I barely touched the cable for the one plug, and
was eletrco-shocked. Didn't feel like trying the others...

I don't normally do anything that has to do deal with the spark plugs, so
haven't noticed this behaviour on other vehicles. But isn't the whole point
in the insulation on the cables to prevent the current from escaping?

I'm pretty sure that the cables are the original stock cables, especially
since the previous owner don't seem to have really maintained the car in
any way. They're in very good condition though, with no visible wear on
them. The distributor don't have any visible cracks, but I haven't yet
gotten to check the inside condition of it. Have no idea what condition the
coil is in, because it's buried so deep in the engine room that I can't get
to it.

Anyhows, I don't need anyone pointing out how stupid it is to touch
high-voltage curcuitry while it's live. I just want to know if it's normal
for the cables to deliver current through the insulation or if I need to
look for faulty components.

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aarcuda69062 - 21 Sep 2006 22:13 GMT

> I've never really noticed this on other vehicles, so I'm not entirely sure
> if this is normal or not, BUT:
[quoted text clipped - 21 lines]
> for the cables to deliver current through the insulation or if I need to
> look for faulty components.

No, not normal.

Replace the plug wires.

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Backyard Mechanic - 22 Sep 2006 02:43 GMT

>> I've never really noticed this on other vehicles, so I'm not entirely
>> sure if this is normal or not, BUT:
[quoted text clipped - 25 lines]
>
> No, not normal.

Yes it IS normal.. for a car with that many miles on it. Especially if
they were the originals which you should be able to tell by looking for
cylinder # markings on them.

This is the PRIMARY symptom of old wires that need replaced.... it's one
cause of difficult starting when there's condensation under the hood.
Insulation degrades over time.. there are pinholes so small you cant see
them

> Replace the plug wires.

Ditto... but dont look for bargains, half the time you might be
disappointed or misled into thinking there's something else wrong.

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Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!

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aarcuda69062 - 22 Sep 2006 03:55 GMT

> >> I've never really noticed this on other vehicles, so I'm not entirely
> >> sure if this is normal or not, BUT:
[quoted text clipped - 27 lines]
>
> Yes it IS normal..

Read his last sentence again.

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Backyard Mechanic - 22 Sep 2006 04:09 GMT

>> > No, not normal.
>>
>> Yes it IS normal..
>
> Read his last sentence again.

Read my WHOLE sentence again

I cant imagine a set of wires that old NOT delivering a jolt when you grab
them... or even if they are half that old.

Signature

Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!

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aarcuda69062 - 22 Sep 2006 04:24 GMT

> >> > No, not normal.
> >>
[quoted text clipped - 3 lines]
>
> Read my WHOLE sentence again

You weren't the original poster.

> I cant imagine a set of wires that old NOT delivering a jolt when you grab
> them... or even if they are half that old.

That wasn't his question.

Leaking plug wires is not normal.

Old leaking plug wires are not unusual.

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Mr. Bunny - 22 Sep 2006 04:46 GMT

>>> On our '92 Tempo w. 175,000 km on it, I was changing the spark plugs
>>> and then fired up the car to make sure it ran ok. Then, before
>>> closing the hood I wanted to double-check if the cables were seated
>>> properly. So while the engine was still running, I barely touched the
>>> cable for the one plug, and was eletrco-shocked. Didn't feel like
>>> trying the others...

{snipped}

>> No, not normal.
>
> Yes it IS normal.. for a car with that many miles on it. Especially if
> they were the originals which you should be able to tell by looking for
> cylinder # markings on them.

Yeah, they definitely have cylinder numbers on them. The rubber is still
very flexible, but I can't tell if they have ever been replaced. If they
have been replaced with original Ford ones, wouldn't they still look stock?

The one thing about the numbers on the wires that confuses me, is that they
say 8 in the distributor end.

> This is the PRIMARY symptom of old wires that need replaced.... it's one
> cause of difficult starting when there's condensation under the hood.
> Insulation degrades over time.. there are pinholes so small you cant see
> them

I wouldn't even have thought of checking the ignition system, if it hadn't
been because the car severely lacked power last we had to take it on the
highway. Was so bad that it was jerky when accelerating over 100 km/h, and
it was impossible to get it up hills at that speed without it slowing down
significantly, and giving some big jumps while fighting up the hill - and
that's while have the gas pedal floored.

That led me to try and replace the parts that Mr. Lube have been telling us
to replace for the past 3-4 oil changes. Sofar I've only gotten to the air
filter and the sparkplugs. I'm a little weary about changing the fuel
filter myself, but on the other hand I'm not to keen on paying a mechanic
$50 to replace a $15 part, and then not be able to tell if they actually
replaced it. Good thing about the fuel filter in this car is that it's
strapped to the wheelwell inside the engine room, so it's easily accessible
(as opposed to being in the fuel line underneath the vehicle which seems to
be common now). Bad thing is that the hose clamps are plastic...

Still have to change the drive belt as well, which is not gonna be an easy
task either, thanks to Ford's "brilliant" design job on this car.

I'm not a big fan of Ford, but we got this car for free. Unfortunately it's
costed us over $1000 in repairs and parts in the last year and a half. And
there's still a long way to go before all problems are solved.

BTW: I ramble, I apologize.

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aarcuda69062 - 22 Sep 2006 14:33 GMT

> Yeah, they definitely have cylinder numbers on them. The rubber is still
> very flexible, but I can't tell if they have ever been replaced. If they
> have been replaced with original Ford ones, wouldn't they still look stock?

No. Replacement plug wires didn't have cylinder numbers on them.

> The one thing about the numbers on the wires that confuses me, is that they
> say 8 in the distributor end.
[quoted text clipped - 10 lines]
> significantly, and giving some big jumps while fighting up the hill - and
> that's while have the gas pedal floored.

Jerking = an ignition miss.

> That led me to try and replace the parts that Mr. Lube have been telling us
> to replace for the past 3-4 oil changes. Sofar I've only gotten to the air
[quoted text clipped - 5 lines]
> (as opposed to being in the fuel line underneath the vehicle which seems to
> be common now). Bad thing is that the hose clamps are plastic...

Plastic doesn't rust.

> Still have to change the drive belt as well, which is not gonna be an easy
> task either, thanks to Ford's "brilliant" design job on this car.
[quoted text clipped - 4 lines]
>
> BTW: I ramble, I apologize.

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