Bryan Feddish sent a clean loaner ECU for me to try in my 84 1.9L. It
looks like this one:

http://gowesty.com/ec_view_details.php?id=4255&search_phrase=ecu&start=

and has part number "025-906-021" on it. It is identified as being correct
for my model/year.

But the ECU in my 84 looks different:

http://picasaweb.google.com/j.michael.elliott/Vanagon/photo#5230048100272871410

It has heatsinky-fins on the plug side, maybe a different mounting pattern
(?), and is labeled "025-906-021C". Says "Digijet" on it.

I presume the two are swappable, given that they have the same part
number. But I want to make sure before I plug the loaner in and either
blow it up, or it makes the engine run backwards (reversing the flow of
time?), or a bad smell or something.

How many ECUs did VW make for the 1.9L?
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR