On 9/17/07, -------- <VW4X4@verizon.net> wrote:
> There is very good reason for these changes!  The reason is it did
> not work very well, just like the surbaru engines.

What didn't work, Idle stabilization?

> Change is and engineering way of admitting failure.

Yep, interesting and pretty accurate observation...

>
> tinker man wrote:
>
> >Hello again,
> >
> >In this never ending saga of analyzing the various versions of ECU's
> >and Idle Stabilization Control Units (ISCU) used in our vans, it seems
> >there was a great variety indeed!
> >
> >ECU's:
> >1. My 1990 Euro-spec Digijet uses a 8049H microprocessor (uP).
> >2. David Kao reports his 1984 US Digijet ECU uses a Z80 (Zilog) uP.
> >3. Jon Kenneke reports his Digifant uses a 6803 uP.
> >
> >I find it quite amazing that VW implemented the same basic technology
> >(digifant/digijet) with at least 3 uP familes!! What a nightmare to
> >manage and update!
> >
> >
> >Likewise, there were many ISCU versions:
> >
> >At least 4 models of ISCU's for 1986-1991 vanagons:
> >251 907 393A Earlier European models
> >251 907 393B Earlier US models
> >251 907 393C Later European models
> >251 907 393D Earlier US models
> >
> >All worked with an additional external ICV (Idle Control Valve).
> >
> >A completely different design (no ICV) was used  for the 1983.5-1985
> >ISCU's that I have no part numbers for.
> >
> >I think it would be beneficial that anyone who has good-quality images
> >of ECU or ISCU internals add them to the VanagonWiki site in the
> >appropriate place and/or forward them to me for further analysis.
> >I suggest each include model year and country, Part number, and at
> >least one good image.
> >Let's see where this takes us (except for overflowing my mailbox...:-)
> >
> >
> >
> >
>