Clarification of Answer by
hummer-ga
on
18 May 2003 11:04 PDT
Hi zula17,
in re: "make sure the choke is operating correctly"
The VW "2000" engine (Type2, 1979-1982) doesn't have a "choke", per se. It
has a Bosch "Air Flow Controlled" (AFC) electronic Fuel Injection (FI)
system that uses other means to acheive the same end: enrichment of the
fuel/air mix at start-up and system controls special to the warm-up.
The AFC 'gas pedal' is really an 'air pedal' - it controls the amount of
air let into the system. This amount is measured and the electronic info
sent to the master control unit ('the brain'), which tells the other parts
of the fuel system what to do in accordance with your foot's command.
The system at start-up is self-regulatory - a real control freak. When
everything is working as it should, it knows better than you do what it
needs to get going and doesn't tolerate human interference well. If you
'give er the gas', you'll disrupt its operation - flood it with air, so to
speak. It's another story once you've 'acheived ignition' and become an
operating part of the system.
Some parts of the 'AFC knows best' start-up / warm-up system to check for
proper function:
- "cold-start valve" (aka, '5th injector'), controlled by a "thermo-time
switch".
- "auxilliary air regulator".
- "temperature sensor 1" and "stator flap" in the "intake air sensor" (part
of the 'air box' where the air filter goes).
All this is not to say that the FI system is causing your hard starts in
winter - just one of many a place to look. As it is said: "there are simple
questions but no simple answers".
The VW system is pretty sophisticated and holistic - it works best when
every part is working well but, as in life or in 20 year-old VWs, one or a
bunch of small things can not be working at their best yet not cause too
much trouble when things are Sweet (balmy weather, flat roads, modest
speeds, etc). When things get Sour (too cold or too hot, mountains, high
speeds, etc), small things add up and troubles seem to come in bunches. For
example: points, gap and dwell, timing, plugs, filters, oil, vacuum leaks -
all fairly straightforward to check and relatively inexpensive parts or
adjustments. They may not cause much trouble in Summer...but will in Winter
when your car is 'stressed' - when everything needs to be tip-top. Check
the simple, easy (and inexpensive) things first: many's the problem solved
with regular maintenance and/or patient and informed observation - whether
by the do-it-yourselfer or the trained mechanic. Still plenty of time
before next winter to work your way up to the horribly complex (and
expensive) things.
If you insist on driving an older air-cooled (and I do understand), I
strongly recommend a good maintenance and repair manual approprate to your
model and year. The Muir "Idiot Book" series is a good place to start, but
many owners also have a Haynes series manual and/or, better yet, a Bentley
series "Volkswagen Official Service Manual". Even if you never crack a nut
or bust a knuckle, at least you'll better understand what the heck your VW
air-cooled mechanic is trying to tell you. At the very least, you'll
discover all the things you should have been doing all this time but
haven't been (ask how I know!).
Also, the VW newsgroups / lists / forums are good places to live and learn
and some are specific to air-cooled Buses, Vana-goners, etc. There are
often "archives" or "faqs" to search through and how-to & technical info to
browse. They're generally a rabble of rabid but helpful folks to listen to
and talk with.
Just some VW thoughts on a gorgeous day, perfect for touring in a Westfalia.
hummer
