I was out in my garage a few minutes ago and started up my wife’s 1990 XJ-S
convertible (5.3L V12 w. Marelli ignition) in the dark. I had read
somewhere about how ignition problems can cause visible sparks around the
distributor, coils and spark plug wires. It was hard to see it at first,
but as my eyes adjusted to the dark, sure enough there were numerous
flashes of blue-white light visible at the spark plug wires.
I replaced the wires (Part Number JLM 11016) last year with an aftermarket
set from a reputable parts supplier in Georgia. After I did a major
tune-up, the engine ran pretty smooth. This car passed CA emissions last
summer with flying colors (0.00% CO and about 4 PPM HC). No evidence of
misfires at that time.
I’ve been trying to track down the cause of a hunting RPM at idle, and
that’s why I was looking at the wires in the dark. I must admit that I was
surprised to see all the arcing and sparking. But I suspect that the
results would be a little different now with the sparking wires and possible
misfires causing my idle hunting. I guess the V12 heat was too much for
the wires.
What brand spark plug wires should I buy to replace these? I have an OEM
Marelli cap and rotor installed. Should I go for the OEM wires?
A quick check on the internet Jaguar parts shops shows the OEM JLM 11016
wires at about $215-220 plus shipping. The aftermarket ones I purchased
were about half that price.
Any recommendations? Other than don’t drive the car until I replace the
wires and you get what you pay for.
Regards,
Paul M. Novak
1990 XJ-S Classic Collection convertible
1984 XJ6 Vanden Plas
1969 E-Type Fixed Head Coupe
1957 MK VIII Saloon
Ramona, CA @Paul_M_Novak1
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Could be dirt and oil…which encourages moisture.
Let’s see what the guys say…
Bill de Creeft----- Original Message -----
From: “Paul M. Novak” pnovak@tmwireless.com
To: v12-engine@jag-lovers.org
Sent: Tuesday, August 22, 2006 10:55 PM
Subject: [v12-engine] Sparking spark plug wires {Scanned}
I was out in my garage a few minutes ago and started up my wife’s 1990
XJ-S
convertible (5.3L V12 w. Marelli ignition) in the dark. I had read
somewhere about how ignition problems can cause visible sparks around the
distributor, coils and spark plug wires. It was hard to see it at first,
but as my eyes adjusted to the dark, sure enough there were numerous
flashes of blue-white light visible at the spark plug wires.
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
Paul, I replaced the OEM wiires with Magnecor wires 5 years ago. They make
sets for the V-12 engine. Mine were about $80 and they are great.
Byrnal Haley
89 XJ-S Convertable, Marelli
I was out in my garage a few minutes ago and started up my wife’s 1990 XJ-S
convertible (5.3L V12 w. Marelli ignition) in the dark. I had read
somewhere about how ignition problems can cause visible sparks around the
distributor, coils and spark plug wires. It was hard to see it at first,
but as my eyes adjusted to the dark, sure enough there were numerous
flashes of blue-white light visible at the spark plug wires.
I replaced the wires (Part Number JLM 11016) last year with an aftermarket
set from a reputable parts supplier in Georgia. After I did a major
tune-up, the engine ran pretty smooth. This car passed CA emissions last
summer with flying colors (0.00% CO and about 4 PPM HC). No evidence of
misfires at that time.
I’ve been trying to track down the cause of a hunting RPM at idle, and
that’s why I was looking at the wires in the dark. I must admit that I
was
surprised to see all the arcing and sparking. But I suspect that the
results would be a little different now with the sparking wires and
possible
misfires causing my idle hunting. I guess the V12 heat was too much for
the wires.
What brand spark plug wires should I buy to replace these? I have an OEM
Marelli cap and rotor installed. Should I go for the OEM wires?
A quick check on the internet Jaguar parts shops shows the OEM JLM 11016
wires at about $215-220 plus shipping. The aftermarket ones I purchased
were about half that price.
Any recommendations? Other than don’t drive the car until I replace the
wires and you get what you pay for.
Regards,
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
I’ve got the Red Magnecore set on mine for 5+ years and never a problem. The
material they are made from is very soft and will tear easily if gripped
with a metal-toothed pliers of any kind. It is much better to use the old
twist-and-pull method with your fingers or a rubber-sleeved wire removal
tool.
-Don Buresh, 1991 XJ-S V12 Coupe, Classic
Orlando
Any recommendations? Other than don’t drive the car until I replace the
wires and you get what you pay for.
Regards,
Paul M. Novak
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I’ve got the Red Magnecore set on mine for 5+ years and never
a problem. The
material they are made from is very soft and will tear easily
if gripped
with a metal-toothed pliers of any kind.
That is my experience. I ruined a couple boots on mine using long
needle-nosed pliers. Fortunately, Magnecore will send new boots free.
I now slip short lengths of hose over the jaws.
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In reply to a message from Paul M. Novak sent Wed 23 Aug 2006:
Paul,
Night is a great time to check wiring, as you did. However, a glow
is often seen on the wires and can be touched and it will flow
around your fingers. This is fairly normal and is corona. The
little arcs you saw are bad news. I suspect the larger wires cause
less corona than the older thinner ones. My XKE had all of the
wires bundled in parallel in a conduit. Such a configuration can
cause cross firing. The bigger diameter is a great deterent.
Noel–
The original message included these comments:
somewhere about how ignition problems can cause visible sparks around the
distributor, coils and spark plug wires. It was hard to see it at first,
but as my eyes adjusted to the dark, sure enough there were numerous
flashes of blue-white light visible at the spark plug wires.
surprised to see all the arcing and sparking. But I suspect that the
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !