Cetin had wrote (written?):
This post on idle stabilization reminded me of something -- my '87 now
seems to idle quite well once it is warm, yet, it takes a long time to
warm up in Pittsburgh, PA for the system to get off the 'cold engine'
mode... Is there an easy setting for what the 'cold' rpm should be, or even
just a screw to adjust how much extra fuel is sent to the cylinders
when the engine is cold? I do not really like the engine racing at
2200 rpm when it is this cold -- I'd feel a lot more at ease if it
idled at around 1500 or so when the engine is cold...
****

i'm not sure if the Digifant (86 on) system actually has a built in 'fast
idle' curve built in to the stabilizer control unit.  in *effect*, when the
stabilizer starts getting gummy, this IS what happens... it runs fast when
cold and then settles down once the engine temp softens any goo/frost within
the little buzzing jobber.  but if i remember right, and someone jump in
here, the factory design is to have the idle stabilize at 950 rpm regardless
of outside conditions.  so even if it is cold enough for your oil to be like
molasses, the stabilizer bypasses enough air around the throttle plate to
keep the idle up at 1000 rpm.  i believe this is how mine operates when i've
just cleaned it... funny how one forgets these things seasonally.  it's
actually a nice system, just prone to the actuator getting gummed up with
sludge from the crankcase breather.  but it is easily cleanable and has
enough range of motion to keep the engine running when it is stiff and cold.

now the 'fast idle' on a pre-86 engine is totally different.  there the
bypass air is regulated with an electromechanical device that has a bimetal
strip that lowers a disk over the bypass orfice.  a heater wrapped around
the bimetal controls the 'warm up' time on this and one can see an authentic
fast idle with this system.  no ECU input.

-dan (in search of an immaculate Westy Syncro??  no. no, my marriage
couldn't take the stress. but gee, if there's anyone out there.....)