[s-cars] Spark Plugs and Coils

[calvinlc at earthlink.net]

Tony,

Bad plugs can cause the ignition coil to go out depending upon what the
nature of the plug deficiency is.  This is especially true of the plug
presents a low impedance from the positive electrode to ground for some
reason.  This happened to me when the positive electrode came loose in one
of my plugs and shorted to the negative electrode causing the coil pack to
fail.

--Calvin


-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of Tony Curran
Sent: Tuesday, March 22, 2005 6:09 PM
To: Tom Mullane
Cc: s-car-list at audifans.com
Subject: RE: [s-cars] Spark Plugs and Coils


Hi Tom,

No it isn't rust. It's rust "coloured". So no water isn't getting in but the
discolouration caused by pressure blowing thru the plug and out where the
ceramic enters the SS body.

Tony
96 S6

-----Original Message-----
From: Tom Mullane [mailto:tmullane at snet.net]
Sent: March 22, 2005 8:04 PM
To: tony.curran at sympatico.ca
Cc: s-car-list at audifans.com
Subject: RE: [s-cars] Spark Plugs and Coils


Tony,

I run a lot of boost.  I would think that anything I get over 15k would be a
bonus.  Maintenance schedule says 30k, IIRC.

As for the rust, it was my assumption that the rust was caused by water
getting by the gasket between the coil pack cover and the valve cover.  Not
really sure how leaking between the ceramic and plug base could happen, and
if it could, how it would cause rust.  The plugs my car came with had this
rust, and it also had rust "high water marks" on the outside of the coil
boots.

Tom




Date: Tue, 22 Mar 2005 19:30:35 -0500
From: "Tony Curran" <tony.curran at sympatico.ca>
Subject: [s-cars] Spark Plugs and Coils
To: "S-Car-List at Audifans.Com" <s-car-list at audifans.com>
Message-ID: <KFEOJHNELNBFOEFPGIBHIEDBCBAA.tony.curran at sympatico.ca>
Content-Type: text/plain;	charset="iso-8859-1"

Hi all,

About a week ago my car started to run very rough and was diagnosed as
having a bad no. 4 ignition coil. This was duly replaced but my mechanic
advised that the spark plugs were in bad shape. Something that I had seen on
them was a rust like discolouring at the base of the ceramic casing just as
it enters the SS body. Mechanic said this is caused due to the plug leaking
- I guess pressure blowing back up the casing of the plug.

So, these plugs were new when I first bought the car and have 52500kms
(approx 32500 miles). I suspect the plugs may have been showing this
discolouration for a few thousand kms but I failed to recognise what this
meant.

Could a bad plug have caused the coil to blow? What is the life expectancy
of th F5DPOR plugs?

Thanks,

Tony
96 S6 - running smooooth again.

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