[s-cars] Diagnosing 1.8t coil pack failures

[Joe Pizzimenti]

Dave,
I think you're chasing the wrong ghost.  With an s-car pushing 25+psi of
boost and a restrictive cast exhaust manifold, I just don't think there's
enough voltage going through these coils to live a longer life.  You're
taking a coil that was designed and tested to live at 7psi and slapping
another 20 on top of it.  I think a CDI is in order if these coils are
really dying this fast.  And it's not as expensive as you think it is,
either.  Get Chrysler 300M coils at 30/per, get a M&W ignition box for 400
or so and wire it all up and you'll be surprised at how much smoother it
will all run.  I know, it's heresay to use a Chrysler part in an Audi, but
your other alternative is to get a Magneti Marelli CDI coil for 500 a
piece.  The 300M piece works just as well, though, up to a certain dwell.

For the money, the 1.8T conversion can't be beat, but Sunday's my bench
racing day.

Joe

On 9/10/06, Dave Forgie <forgied at ae.ca> wrote:
>
> Well, after a year of driving my 1.8t coil pack conversion experiment, I
> finally (inevitably?) had a coil pack fail. Its been coming on for
> awhile, i.e. some missing/ hesitation under boost (24 psi plus) but
> nothing in "normal" driving.  Just like a "real" coil failure mode.
> Like the OE system and a POS failure, you can't find the offending
> cylinder until you get a total failure, i.e. a failure at idle.  As a
> result, diagnosing which cylinder is the problem is the same as tracking
> down a OE POS channel failure:  1) Remove the injector cover 2) Start
> the engine (in neutral with the hand brake on) 3) pull the injector
> connectors one at a time. Since you will be going from a 4 out of 5
> cylinder mode to a 3 out 5 mode, it is very clear which cylinder has the
> problem.  In my case, based on other failures, I was willing to bet it
> would be no. 5.  Wrong:  No. 3.  Solution: disconnect the coil pack from
> the harness, pull coil pack, remove rubber "seal" ring from dead coil
> pack, add seal ring to new coil pack, insert new coil pack (to engage
> the hex part of the plug), reconnect to harness, start car.
> Purrrr.....Total time from removing injector cover to finish: 5 minutes
> (and some of that was wiping dirt off the fuel rail).  Now to find out
> whether the 115 R coil packs are really any better.
>
> Dave F.
>
>
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