Date:         Thu, 28 Sep 1995 13:30:16 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         jlfoster@siu.edu (John Foster)
Subject:      Temperature Related Performance Problems

Can anyone help with two apparently temperature related problems in my 1986
Vanagon which have irratated me for years?  

First is a tendency for it to cut out (similar to just before running out of
gas) after extended (several hours) consistent highway speed on cool
days---45 F range. This has been an unwelcome part of spring vacation trips
for the full life of the vehicle [summer and winter trips go fine].  It
never has actually stalled, but it's annoying nonetheless.  Needless to say,
I never have been able to replicate this symptom in a shop to get a clear
diagnosis, although one dealer told me it might clear up if I pulled off the
road, turned off the engine, and restarted it.  He said something may be
jamming the ECU memory--restarting may clear it.  

The second problem has developed over the past few years.  On warm (55-65 F)
AND damp days the engine stalls at cold idle.  You can keep it running with
a foot on the accelerator until it warms up...then it runs OK...but again
it's annoying.  (Dealer said I should just warm it up in my driveway on such
days before leaving). This problem does not occur on dry days, or hot and
damp days for that matter.

In general this engine has run fine for 110 K miles now.  I do check idle
speed and timing routinely, but have not checked CO% for a long time. I
replaced the oxygen sensor as scheduled @ 60K miles, ignition wires @ 85K
miles, and had a VW recall of fuel tank and ECU unit performed a long time
ago.  Hence none of these seem related to these problems.  I tested the
coolant temp sensor once for resistance (chart in Bentley manual) at
whatever the temp was that day--probably 80 F--but did not check it over the
full range.  The throttle valve switch occasionally sticks on this car (i.e.
is not always at continuity at cold start) but can be freed by tapping the
accelerator before starting--which I usually remember to do.   

Any thoughts??  Test the temp sensor resistance across a range of
temperatures or does something else seem more likely??? 

                                                John Foster
JOHN L FOSTER
DEPARTMENT OF POLIICAL SCIENCE
SOUTHERN ILLINOIS UNIVERSITY
CARBONDALE, IL 62901-4501

Tel:  (618) 453-3172 (office)
      (618) 549-7760 (home)
fax:  (618) 453-3253
Email: jlfoster@siu.edu