Hello Volks,

As part of my analysis work regarding the Vanagon Idle stabilization
control unit (ISCU) some of you might be aware of, both here on the
list as well as on VanagonWiki, I've received much feedback about
inter-compatibilites between the various units, e.g. Digijet ECU
working with both old style (ignition timing modulation) and new (idle
control valve modulating air supply) Idle stabilization control units.

Also, I'm aware of 4 models of the later 1986-1991 vanagons Idle
stabilization control units:

251 907 393A Earlier European models

251 907 393B Earlier US models

251 907 393C Later European models

251 907 393D Earlier US models

The main question is are all versions a drop-in replacement for each other?
I doubt that, because the US models were designed to work with
Digifant ECU's, while the Europeans were for the Digijets and were
more powerful (112BHP)..
Also, Internal circuitry is similar but definitely different between
all models.

Any educated opinions?
Cheers,
TM