the bogging down symptom could be dead spot on your AFM

On Sat, Apr 11, 2015 at 2:43 PM, Neil N <musomuso@gmail.com> wrote:

> 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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>
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>
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>