Date:         Fri, 25 Feb 2005 09:39:54 -0800
Reply-To:     Kevin Matlock <k.matlock@VERIZON.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Kevin Matlock <k.matlock@VERIZON.NET>
Subject:      90 syncro westfalia bogging problem
Content-Type: text/plain; charset="us-ascii"

Hi all,
I have a '90 syncro westy with an occasional bogging problem when I try
to accelerate.  It doesn't occur all the time and has only come up on
longer drives.  When it's happening I can slow to a stop and the engine
remains idling perfectly; if I try to accelerate away from the stop it
again bogs.  When this happens my response is to either (A) SLOWLY apply
gas and milk the engine to a higher RPMs... this seems to allow whatever
components to react to more fuel being introduced into the combustion
-OR- (B) pull over and turn the van off... usually sitting for 15
seconds is enough to "reset" the issue and it's fine until the next time
it wants to act up.
I have driven the van many miles using the "A" approach but the van
responds with a delayed reaction; it works, but just not fun and not
easy to drive.

The problem doesn't happen at all when I drive around town or commute to
work.  Most of these trips are under 30 minutes.  There seems to be two
situations that it acts up:

- After more than about an hour at a constant highway speed, I try to
accelerate and the van slows down.  The issue can happen either if I'm
manually on the gas or if I have the cruise control on.  I would
estimate the issue occurs about 25% of the time under these
circumstances.

- Another time it happens is more consistent (more like 75% of the
time).  Occasionally I drive from sea level up to 6000'.  As I drive up
the road to this elevation very often the van is bogging as I ascend.  I
am left to just keep constant pedal position to allow me to chug up the
hill (after a down shift and getting back on the gas it really SUCKS!).
When it's time to head down the van fires right up and idles fine (the
coolant has cooled by this time).  As I descend down the road to a stop
sign situated at 4000' the van is happy... but as I try to pull away
from the stop sign it bogs.

To me, the symptoms seem to somehow indicate temperature.  When the van
is cool it somehow doesn't read the correct fuel ratio?  I don't think
it's directly tied to elevation since it can also happen at sea level on
the multi-hour freeway trips.

Some quick details of the van if it helps troubleshoot.
'90 syncro westy, 163K miles, 13K (one year) on a rebuilt 2.1 AVP engine
Replaced the temp II sensor since I thought this was the issue
When I got the van it had the infamous vanagon syndrome issue.  This has
been totally eliminated with soldering in the resistor as prescribed by
several websites as well as installing the replacement/upgraded wiring
harness.  I did the resistor/harness trick to fix the old bucking
problem, but I did this a while ago with my old engine.  This new
bogging issue seems to only have sprung up since I replaced the engine
last March.

Any thoughts or help would save my further from pulling my hair out!
Kevin Matlock
90 Westy "Big Red"