Michael & Carol Ostrouch wrote:
>
> Hi all ya Vanagon experts.
>
> Our 91 Westy runs great once warmed up.  However we have to sit at a
> idle until
> it warms up to normal temp before we can drive.  It starts hard at times
> and will stall
> if you try to drive before it's warmed up.
>
> It would seem some temp sensor is sending out the wrong message?
>
> Does anyone out there have this problem, and better yet the answer to
> this problem?
>
> Thanks in advance
>
> Michael & Carol Ostrouch of Central New York
> 91 Westy
> 71 Beetle

Hi folks,

You're right it could be the coolant temp sensor. You can check it with
an ohm meter. pull off the sensor plug and check the resistance value of
the two pins. When cold it should be >2,000 ohms, when full hot the
meter should read ~400 ohms. See the Bentley book for sensor ID and
specific temperature - resistance values. If the cold resistance value
is off (less resistance) it will create the very symptom you discribe.

Often the coolant sensor gets "shot in the head" when the problem is
elsewhere. You could have an unmetered air leak or a O2 sensor
malfunction.

To check the O2 sensor unplug the sensor wire with ihe ignition off and
then cold start the engine and monitor the symptom. A shorted sensor
could cause your symptom (but not likely).

An unmetered air leak will be most noticeable when cold. The lean
condition caused by an unmetered air leak will cause poor cold starting
& running with very poor acceleration.

The O2 sensor doesn't function below ~300*C (572*F) so the air leak
condition is not corrected and the lean running symptom is present. When
the O2 sensor warms up to >300*C additonal fuel is provided by the
digifant system and the lean condition "goes away". Look for air
entering the engine AFTER the air flow meter.

Good luck     JP