Hi all.

This is for an '88 2.1 WBX with Digifant. The idle stabilization valve
and control unit are currently unplugged. (see below).

However. If: engine systems are working correctly, IS system is
connected, no other loads are on engine (AC, PS, heater etc.), when
accelerating from a dead stop, does the throttle switch act as an
input?  i.e. if that input were missing, would this cause an
occasional bog when accelerating from a dead stop?

I would think it doesn't make any difference given that the IS system
should only affect the engine at idle, but then I have to wonder if
there's a transition of sorts that happens when accelerating from a
dead stop. i.e. at idle, air that is bypassed into intake plenum via
ISV is closed off as the throttle opens. (throttle switch input?)

Regardless if engine off (ign. on) or "1" wire connected or not,
engine running, the valve draws far less than the ~ 420 mA spec. Like
around 130 mA VAC. The valve buzzes and I can blow air through it when
it's operating. The engine runs ok otherwise but has the occasional
minor bog accelerating from a dead stop. The worst bog so far, was
during a trip in Harrison Lake area here in BC. While traveling back
out of camp, we pulled over on a hill. When I went to accelerate from
dead stop up the hill, the van took some time before accelerating.
Accelerator pedal about 1/2 down made no difference. In a second or
two, the engine "caught up" and accelerated. I can't see how the idle
stabilization valve would figure into this though.

FWIW, my local parts guy pointed me towards the Audi 5000 as a
possible parts source for a used valve. I'll search more on this, but
found this page interesting:

http://vnc.thewpp.ca/stuff/bentley/ep0niks.ctech.ca/vw/eva2/FU01/ch6.3.2.html

Via a linked page there, I see mention of 2 and 3 pin valves. I don't
know if all 2.1 WBX digifant engines have this, but the ISV connector
on my '88 has a 3 pin housing with only 2 pins being used.

I would think a CIS-E ISV is harder to find than the Vanagon part but
it may suffice?

Neil.

--
Neil n

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