On Sun, 17 Jun 2012 14:06:01 -0700, Old Volks Home <oldvolkshome@GMAIL.COM>
wrote:

>In general, the Ignition Module (ICU) on 80-85 models (the one on the
>left engine wall) is a sealed unit, so repair of these is extremely
>difficult, if at all.

How is it sealed, with epoxy? I wasn't planning to repair it but rather be
able to test it externally. It's just an amplifier for the HALL sender
signal + some kind of power transistor driver for the ignition coil.
Probably just a few transistors/resistors/capacitors. How complex can the
circuit be?...

> The module on the 86-91 models is integrated
>inside the ECU, so there is a remote chance that can be serviced.

If it's the power transistor driver in the ECU that's gone bad, it can be
serviced.

>The Hall Unit in the distributor (80-85 and 86-91, which both are
>different) is another minefield when it comes to a field repair.

Yep, because you also have to set the timing again after dismantling the
distributor. Still, I wonder if there's active circuitry inside the hall
sender device because it gets 12V power. Once I know the circuitry, it'll be
much easier to diagnose a problem. Currently I have a rare intermittent in
the hall sender, maybe it's just a loose wire much easier to repair than
replace the whole sender or distributor.

>I carry a spare of each with me on both my 84s since losing a hall
>unit function near Klamath Falls, OR in 1998.

How do you set timing on the road without a timing light?

> If I owned an 86-91, I  would always carry a spare ECU.

Yep, that's my goal too, also with the digitool interface and display box
which will keep me out of the dark in case of a failure.

>But that's just me, based on on a 50+
>year habit of carrying critical spares (Cables, etc.,) for my VWs.

50+?...wow! I won't guess your age...
That's a good habit even for younger drivers. I'm trying to improve in this
respect, though from my experience field diagnosis often helps solve the
problem even without part replacement (loose/dirty connectors somewhere).

>You'd be surprised at what I carry for replacement spares in Rear
>Seatbox of my Westy.

It would be interesting to hear the highlights...:D