Re: Update - 5KS Starts, Runs, Dies???

[Kneale Brownson <knotnook@traverse.com>]

At 09:22 PM 11/22/99 -0500, Tom Serrago wrote:
>Hi All,
>
>I would like to thank all of those who responded with suggestions to my
>problem, I'm happy to report all is well again. Because of the no spark
>condition, I first checked out the ignition system as best as I could,
>cleaned contacts, etc. It has been about one year so I decided to replace
>the rotor, d-cap and plugs ( all bosch, old and new), as well as air and
>fuel filters. All parts looked in good shape with no excessive wear or dirt.
>I ran the hell out of her, started, shut down, restarted at various
>intervals. No problems at all, but what the hell happened anyway!
>Now I'm scratching my head, but pleased, after 14 years with this car I
>figured I should have known. As I am about to toss out the old parts, I
>notice this little crack in the blackish insulation material on top of the
>rotor near the outer edge. After prodding and poking I noticed that contrary
>to my belief, there is no solid strip of copper running from the center to
>the edge, the middle consists of some sort of semi-conductor material. I'm
>guessing that this crack must have been the cause of the intermittent no
>spark condition, especially when hot.
>Always something new ( I'm just waiting for the A4 to start getting cranky),
>anyway thanks again.
>
>Tom Serrago
>85 5KS Avant
>99.5 A4 1.8T QMS

I once had a Porsche that would misfire and run rough when thoroughally
warmed up, especially on hot days.  Started cold and ran great until driven
an hour or so.  After hours of the mechanic's testing/retesting everything
in the ignition system, he replaced a distributor rotor that had been put
in new just a few weeks earlier and solved the problem.  On looking at that
copper strip you mentioned, he could see with a magnifying glass that there
was a crack that apparently would open enough when the materials became
heated to cause the misfiring.   

Kneale Brownson