I'll second Scott's recommendation.  A few years back, by Digijet 1.9
ECU took a dump in the Texas Panhandle.  I always carry a spare :)

Digijet ECUs are abit more robust than the Digifant successor in my experience.
-- 
Jim Thompson
84 GL 1.9 "Gloria"
84 Westfalia 2.1 "Ole Putt"
72 411 Station Wagon "Pug"
75 914 1.8 "Nancy"
Full Timing Since March 1999
oldvolkshome@gmail.com
http://www.oldvolkshome.com
***********************************
On Sun, Feb 27, 2011 at 3:16 PM, Scott Daniel - Turbovans
<scottdaniel@turbovans.com> wrote:
> Given that :
>
> the van and engine can not run at all if the ECU fails, or some other lesser
> failure occurs ..
> I heard of one that wouldn't supply ground for the fuel pump relay for
> example...
>
> and
> it's a small light weight part ....
> and
> having on could totally save your butt, or some of VW person ..
>
> I can't see not having one on trips.
> That's like not taking a Bentley manual on a trip ...
> it's essential equipment if you want to do any self-rescue.
>
> Scott
> turbovans
> ----- Original Message -----
> From: "David Beierl" <dbeierl@ATTGLOBAL.NET>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Sunday, February 27, 2011 2:23 PM
> Subject: Re: Spare ECU
>
>
>> At 01:32 PM 2/27/2011, Don Hanson wrote:
>>>
>>> It's my understanding the ECUs seldom fail..so seldom that while I have
>>> one,
>>> (for diagnostic reasons) but I usually leave it home when I travel, to
>>> make
>>> room for other spare items that are known to be more likely to fail...
>>
>> Was me, I'd carry it. �Subtle/intermittent ECU problems will drive
>> you mad. �Given an available ECU, swapping it in would be right up
>> there on my list along with unplugging the O2 sensor as things to do
>> before you even begin trying to diagnose driveability problems
>> (slight overstatement, but fixing it would make this a very long post).
>>
>> Oh! �You're running an in-line engine, yes? �All my VW experience is
>> with WBX, so YMMV.
>>
>> Yours,
>> David