View Full Version : Would a bad sparkplug wire cause:
usshopkins@yahoo.com
October 29th 05, 09:00 PM
Hi Everyone,
I've had a problem for the past 3 years and it's gotten worse
as the time has gone on. It's a 1997 Buick Riviera 3.8 supercharged
engine. Two problems are it will just stall while sitting at a red
light (sometimes it catches itself though) and second, at around 160
degrees the car wont start, it just turns over. Recently it stalled
going 45MPH.
So I changed my sparkplug's and sparkplug wires today for the first
time ever. I only have 85,000 miles so the plugs should still be good
(GM claims 100,000 miles, yeah right). Anyway, I noticed that when I
removed the #4 sparkplug wire from coil, the connector on the coil was
completely rusted. I wire brushed the connector and made it shiney
again and continued on. After I was done I checked the OHM's of each
old sparkplug cable. The number 4 cable didn't read anything at all. I
cut the boot off and it appears that the metal wire within the
sheathing was rusted off. It appeared to still be in the cable
(somewhat) but was not touching the connector that touches the coil at
all.
The car otherwise runs fine with no loss of power or knocking, etc. It
passed emmisions inspection. So my question are:
1. Could my car run without sparkplug 4 OR is there enough voltage
being pumped out at the coil that the spark could make it through the
air, to the wire within the plug wire and still have enough juice to
generate a spark at the #4 plug?
2. Would having one spark plug out stop a car from starting?
See picture at: http://www.wildlifereserve.org/sparkplug.jpg
Shep
October 29th 05, 09:41 PM
Put wire and plugs in it you are very due! When it doesn't start do you have
spark?
> wrote in message
oups.com...
> Hi Everyone,
>
> I've had a problem for the past 3 years and it's gotten worse
> as the time has gone on. It's a 1997 Buick Riviera 3.8 supercharged
> engine. Two problems are it will just stall while sitting at a red
> light (sometimes it catches itself though) and second, at around 160
> degrees the car wont start, it just turns over. Recently it stalled
> going 45MPH.
>
> So I changed my sparkplug's and sparkplug wires today for the first
> time ever. I only have 85,000 miles so the plugs should still be good
> (GM claims 100,000 miles, yeah right). Anyway, I noticed that when I
> removed the #4 sparkplug wire from coil, the connector on the coil was
> completely rusted. I wire brushed the connector and made it shiney
> again and continued on. After I was done I checked the OHM's of each
> old sparkplug cable. The number 4 cable didn't read anything at all. I
> cut the boot off and it appears that the metal wire within the
> sheathing was rusted off. It appeared to still be in the cable
> (somewhat) but was not touching the connector that touches the coil at
> all.
>
> The car otherwise runs fine with no loss of power or knocking, etc. It
> passed emmisions inspection. So my question are:
>
> 1. Could my car run without sparkplug 4 OR is there enough voltage
> being pumped out at the coil that the spark could make it through the
> air, to the wire within the plug wire and still have enough juice to
> generate a spark at the #4 plug?
>
> 2. Would having one spark plug out stop a car from starting?
>
> See picture at: http://www.wildlifereserve.org/sparkplug.jpg
>
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plainoldmechanic
October 30th 05, 08:21 PM
by all means spark can "jump" or travel through a bad or broken wire.
eliminate yor problems by replacing both the plugs and wires. use only
O.E. PARTS. (ORIGINAL EQUIPMENT) then have your car hooked to a
competent scanner to locate further problems. it will save you $$$$$$
that you will undoubtably spend by simply replacing parts.
Mike Romain
October 30th 05, 08:39 PM
Yes 'and' yes for number 1, No for number 2.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
wrote:
>
> Hi Everyone,
>
> I've had a problem for the past 3 years and it's gotten worse
> as the time has gone on. It's a 1997 Buick Riviera 3.8 supercharged
> engine. Two problems are it will just stall while sitting at a red
> light (sometimes it catches itself though) and second, at around 160
> degrees the car wont start, it just turns over. Recently it stalled
> going 45MPH.
>
> So I changed my sparkplug's and sparkplug wires today for the first
> time ever. I only have 85,000 miles so the plugs should still be good
> (GM claims 100,000 miles, yeah right). Anyway, I noticed that when I
> removed the #4 sparkplug wire from coil, the connector on the coil was
> completely rusted. I wire brushed the connector and made it shiney
> again and continued on. After I was done I checked the OHM's of each
> old sparkplug cable. The number 4 cable didn't read anything at all. I
> cut the boot off and it appears that the metal wire within the
> sheathing was rusted off. It appeared to still be in the cable
> (somewhat) but was not touching the connector that touches the coil at
> all.
>
> The car otherwise runs fine with no loss of power or knocking, etc. It
> passed emmisions inspection. So my question are:
>
> 1. Could my car run without sparkplug 4 OR is there enough voltage
> being pumped out at the coil that the spark could make it through the
> air, to the wire within the plug wire and still have enough juice to
> generate a spark at the #4 plug?
>
> 2. Would having one spark plug out stop a car from starting?
>
> See picture at: http://www.wildlifereserve.org/sparkplug.jpg
oldkid
October 31st 05, 06:37 AM
it seems economy is a primary concern.even if just on principle.what
i do is remove end off wire and cut back to good "wire"1/2 inch at a
time.then put end back on.then test wire for spark by putting back on
coil and sticking a spare sparkplug in boot and grounding.(lay on
engine)do not hold plug while engine is turned over.or just replace
that wire.if problem persists.consider complete tune-up.
Lawrence_Glickman
October 31st 05, 06:47 AM
On 30 Oct 2005 22:37:21 -0800, "oldkid" >
wrote:
> it seems economy is a primary concern.even if just on principle.what
>i do is remove end off wire and cut back to good "wire"1/2 inch at a
>time.then put end back on.then test wire for spark by putting back on
>coil and sticking a spare sparkplug in boot and grounding.(lay on
>engine)do not hold plug while engine is turned over.or just replace
>that wire.if problem persists.consider complete tune-up.
I might add that on modern engines a certain amount of resistance is
expected in the spark plug wires. So many Kohms / foot. If you are
within a factor of 2 of the factory specs, you might be able to trim
the wire back. But if you get into the 5 or 10 factor range of error,
you can screw up your ignition module and ruin your engine.
The ignition module in a modern engine is _designed_ to expect a
certain resistance in the plug wires. The plug wires are in fact part
of the design parameters for the ignition pack.
It is a good idea when buying replacement wires to check them with an
ohm meter, to be sure you are _close_ to factory specs. Or you can
fry some stuff in your engine, the main thing being the ignition
module. And then you replace it, and fry it AGAIN. And this ****
keeps going on forever, because you =have= to be within tolerance of
the design parameters for the 30,000 volt and up circuit.
It is best to stick with OEM wires from a dealership when replacing
your plug wires. And route them _exactly_ as the originals are
routed, or you can have *crosstalk* between them, which will further
screw things up.
Pay the extra bucks and get OEM wires from the car dealership. And it
isn't only a matter of the resistance, the insulation characteristics
of the wires are just as important.
Penny wise, dollar foolish, when it comes to replacing or *shortening*
plug wires.
Lg
oldkid
October 31st 05, 04:01 PM
since the voltage going thru the plug wire is an result of indirect
voltage generated in the coil windings how would the ignition module
be affected?where is the feedback encountered?even though a system is
designed for a certain plug wire resistrance,does this does imply a
catastrophic failure due to being out of spec.the only thing i can
imagine is the coil either internally or externally shorting its high
voltage to nearest ground which could be the module in the case of a
highly resistant plug wire(misfire).is that what you meant.
Mike Romain
October 31st 05, 04:20 PM
I have had 'missing' when wet issues when stuck way back in the deep
bush and have cut off a couple wire ends and put them back on. I carry
a multimeter though so I knew when I had good wire.
The last time I did this, I drove an extra 75 miles return from the
trail head when I went out for gas to get new OEM wires before going
back to the campsite which was 25 miles from the nearest house.
In my mind, once a wire has gone rotten, it is time to change the wire
and the distributor cap that it plugs into. A good shot of dielectric
grease helps keep them from rotting.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/index.html?id=2120343242
(More Off Road album links at bottom of the view page)
oldkid wrote:
>
> it seems economy is a primary concern.even if just on principle.what
> i do is remove end off wire and cut back to good "wire"1/2 inch at a
> time.then put end back on.then test wire for spark by putting back on
> coil and sticking a spare sparkplug in boot and grounding.(lay on
> engine)do not hold plug while engine is turned over.or just replace
> that wire.if problem persists.consider complete tune-up.
Lawrence_Glickman
October 31st 05, 06:45 PM
On 31 Oct 2005 08:01:30 -0800, "oldkid" >
wrote:
> since the voltage going thru the plug wire is an result of indirect
>voltage generated in the coil windings how would the ignition module
>be affected?where is the feedback encountered?
I think it is a question of how much current is being supplied by the
ignition module, not just a voltage issue. If you're running plug
wires that have a much lower resistance than OEM, then you're
demanding more current from the Ignition Module during each plug
firing. Over time ( how much? )...this can't be a good thing for the
Ignition Module. It could/would lead to overheating of the IM,
overloading of the circuit providing the spark voltage.
If you're saying that the coil is self-limiting in the amount of
current it =can= deliver, because of its design, that is right, so the
means of damage is unknown until/unless I can get a schematic for the
IM in question. All I can say, is you will find this information on
the WWW regarding plug wire resistance and the necessity for it to be
correct for the circuit in question.
I suppose you can do a Test and report back to this n/g with your
results. Run Stranded Copper Wire instead of spark plug wire, from
your IM/coil pack to your plugs. If you make it to town and back, be
sure to open the hood to see where the smoke is coming from.
Lg
>even though a system is
>designed for a certain plug wire resistrance,does this does imply a
>catastrophic failure due to being out of spec.the only thing i can
>imagine is the coil either internally or externally shorting its high
>voltage to nearest ground which could be the module in the case of a
>highly resistant plug wire(misfire).is that what you meant.
aarcuda69062
October 31st 05, 11:17 PM
In article >,
Lawrence_Glickman > wrote:
> On 31 Oct 2005 08:01:30 -0800, "oldkid" >
> wrote:
>
> > since the voltage going thru the plug wire is an result of indirect
> >voltage generated in the coil windings how would the ignition module
> >be affected?where is the feedback encountered?
>
> I think it is a question of how much current is being supplied by the
> ignition module, not just a voltage issue.
The ignition module _does not_ supply current.
It switches the primary current on and off, nothing more.
> If you're running plug
> wires that have a much lower resistance than OEM, then you're
> demanding more current from the Ignition Module during each plug
> firing.
Secondary resistance has absolutely nothing to do with primary
current. There _are_ methods of identifying secondary resistance
problems by analyzing primary current, but that would be getting
a little ahead of the game in this case.
The particular vehicle in question _does_ employ circuitry to
limit primary current independent of secondary resistance and/or
voltage.
> Over time ( how much? )...this can't be a good thing for the
> Ignition Module. It could/would lead to overheating of the IM,
> overloading of the circuit providing the spark voltage.
Happens once the secondary resistance causes secondary voltage to
exceed the dielectric strength of the weakest component of the
secondary which usually happens to be the shellac coating the
windings of the coil secondary, but it's strictly a function of
voltage, not current.
> If you're saying that the coil is self-limiting in the amount of
> current it =can= deliver, because of its design, that is right, so the
> means of damage is unknown until/unless I can get a schematic for the
> IM in question. All I can say, is you will find this information on
> the WWW regarding plug wire resistance and the necessity for it to be
> correct for the circuit in question.
He's asking about trimming back a few inches of the plug wire and
re-crimping the terminal at the end where the wire fried. No big
changes there once one considers that this is well within the
differences in plug wire length normally found on such a vehicle.
> I suppose you can do a Test and report back to this n/g with your
> results. Run Stranded Copper Wire instead of spark plug wire, from
> your IM/coil pack to your plugs. If you make it to town and back, be
> sure to open the hood to see where the smoke is coming from.
Copper core plug wires cause EM type interference and are likely
to radiate electrical noise that other sensitive circuits are
unable to cope with, the ignition coils themselves probably
wouldn't care one bit.
November 1st 05, 01:44 PM
"Mike Romain" > wrote in message
...
> In my mind, once a wire has gone rotten, it is time to change the wire
> and the distributor cap that it plugs into. A good shot of dielectric
> grease helps keep them from rotting.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
That is my experience too, Mike.
You might jury rig a wire and get back to civilization, but it is false
economy
to 'doctor' spark plug wires.
The carbon conductor wires can be fragile enough without cutting on them.
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