[s-cars] Repairing an UrS4/S6 POS

[Varon H. Fugman]

Wow, never would have expected a disconnected wire inside the POS module!
I'm going to have to pry the cover off an old failed one to see if that's
what happened.  Wonder if the heat made it unsolder itself, or it broken
from vibration?

Back when I was running stock coils I had the typical POS failures.  At one
point they were so frequent I was going to make a patch panel so I could
switch over to the spare channel without having to move pins in the
connectors!

I figured it was heat frying the electronics, so I was considering
remounting the POS modules on the air box as in some V6 cars.  Also thought
it should be possible to design a more robust circuit using a heavy duty
MOSFET, but it's been way too long since I took electronics in college.

But then I starting running 1.8t coils (using an 034 harness) which at first
failed like crazy (poor quality coils 034 supplied with the kit), then only
every couple years (later revision VW 1.8t coils) and now not at all (VW
2.0t coils.)

Varon
'95 urS6 w/2.0t coils
'07 Jetta 2.0t

Addendum: In fact, the only 2.0t coil I have had fail is in our '07 Jetta.
I was puzzled at first how to determine which one as bad, as you can't just
unplug injectors on the 2.0fsi motor--they are buried way to deep to get to
the connectors.  Then I realized I had the perfect test device in the other
garage bay, so I just pulled all 4 coils out of the Jetta, stuck them in
cylinders 1-4 of the S6 and quickly located the bad coil using the standard
technique!