I don't work on those anymore ..
but I'll throw a few things out ..

on one I saw .......there were ground wires , just push-on spade type,
under the intake manifold..
those can't make very good connection after a while.

the temp sensor is a sngle wire one screwed in to the left head ..
where it can corrode.
It's noteworthy that on the next generation up ..
the 1.9 wbxr that same temp sensor doesn't depend on grounding through
where it's screwed in ..and instead has two wires..one signal, one ground.

also ..I suspect you have a non-Ca model with points igntion ..
that's totally bogus ..
convert to electronic ignition.
there's after market of course..
but a 1.9 wbxr distributor, ignitor, and small wiring harness and coil
works nicely.

but ...check all specs.   I find all kinds of things out of whack on
waterboxers all the time.

scott
www.turbovans.com

On 3/20/2012 10:57 AM, Karl Ploessl wrote:
> it's an 81 aircooled vanagon:
> in the morning (outside temperature ~50), it immediately starts. But
> later in the afternoon (around 5 pm) it turns over but doesn't fire
> up. Only playing with the gas pedal makes it eventually run. I noticed
> that behavior the last couple of weeks when it got warmer (afternoon
> temperatures are in the 80s now). Any suggestions what to look for?
>
> Karl
> 1981 Westy "Jenny"
> 2000 VW Jetta GLS VR6
> Wilmington, DE
>