x2 on making sure contacts are clean. And....
Ensure ECU plug is seated properly. Like it "clicks" into place.
check condition of wires at ECU plug.
On ECU's-harneses I've seen, the wire
cases looked fine. But. I've read that if moving the wires at that point
affects engine performance, this may indicate a flaw at wire near connector.
In my limited experience, that's unlikely; they're well protected.
More likely is a failure at a solder joint inside ECU.
Were it me, I'd open the ECU and insect the PCB for flawed solder
joints and/or heat damaged parts, water damage (unlikely)
I may be wrong, but isn't the Shoe Box limited to only reading inputs?
i.e. it may not be able to determine if the ECU itself is at fault?
(per se. As with Bentley, if all else is ruled out as OK, the ECU
is the last part of trouble shooting?)

On 7/12/15, John Goubeaux <john@ucsb.edu> wrote:

> So, ECU swap and start-up went fine. Idling was too high and car ran
> rich after the swap ....SO  while not a "brick" the ecu is NOT "good to
> go", but maybe good for a spare OR a core on a rebuilt one.
>
> I did get a "shoebox electronics" ECU monitor

--
Neil n

Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>

1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>

1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>

Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>