Help!

My '85 Vanagon has trouble getting started.  Here's the scenario: 

What I do                         What happens
---------                         ------------
I get in and turn the key.        The engine starts almost immediately, runs
                                  for about a second, and then quits.

I turn the key again.             The starter cranks for as long as I hold the
                                  key, but the engine only stumbles a couple
                                  times and never catches fire.

I repeat the previous step        The starter gamely cranks the engine but 
several times until I give up     with each iteration the engine stumbles less
in disgust or the battery         often and eventually never fires a single
wears down.  (I have also         cylinder.
tried this while boosting the
battery via jumper cables from
my wife's Jeep -- which *always* 
starts, by the way...)

Here are some other clues:

The problem is worse when it's cold outside.  Yesterday and this morning the
temp was around 20F and I couldn't get the beast to start for squat.  
Yesterday I was able to drive the Jeep to work but today I rode my bike 
(18mi. each way ... brrrr!!). 

When the temperature is above 40 or so then I can usually start it by partially
depressing the accelerator when the engine catches and then driving away 
immediately.  The engine runs rough for a couple minutes while I'm driving 
(in a low gear) but then runs smoothly thereafter. I can smell gas when I'm
backing out of the driveway.

I have a couple theories.  The first is that I'm flooding the engine by repeated
cranking (it seems more likely to fire after I let it sit).  The problem here
is that it doesn't explain why the engine runs rough after starting on the
first or second try.  The second is that there's something screwed up in the
FI system that's causing the starting mixture to be richer the colder it gets
outside.  I'm going to do some electrical tests tonight (per Bentley) if I can
get the garage cleared out.. and then get the beast into the garage (the 
driveway's uphill).  It would sure be nice if the Bentley folks included a
little 'theory of operation' with all their pretty pictures -- they're a 
little thin on troubleshooting info, I find.

So if you've made it this far then you must care :{) .  Can you help me?

-- 
Chris Getschow (getschow@an.hp.com, ringo@aerodyne.com) 
Bedford, MA
'85 Vanagon GL