After digging my Vanagon out of the melting snow today I was able to install
the new-to-me ISC and ascertain that it was in fact the culprit in my
no-idle-at-cold-start problem. Hooray for that but now I'm am left very
curious about what fails in these units.

I did a fair bit of archive searching and read some old posts about
particular capacitors within the units looking burnt or toasted and one
enterprising fellow that actually replaced said capacitors. Someone, I think
John Bange, started to map the circuitry but it seems to be a project that
died. I have taken the defective unit apart and seems almost comical in its
design and construction - so many resistors, transistors and capacitor! None
of them appear damaged to my eye so I'm wondering what has failed.

Has anyone here successfully repaired one of these units and has anyone
figured out how to identify the failed circuit within?

--
mordo
1990 Carat