Hey Tom. This is what I was thinking as well. FWIW.

As for the 50 wire to the ICU, and I think Scott (Turbovans) has
mentioned this, but I think the wire from 50 to the ECU causes the ECU
to "rich" up the mix (and adjust timing??) to ease starting. Maybe the
50 wire to ICU disables the ICU during cranking so the idle control
valve doesn't change during cranking?

Neil.

On 11/14/13, Tom Carchrae <tom@carchrae.net> wrote:

> Another WAG;  the power steering pump, etc (which is not on my van) are
> probably to avoid low engine revs before they happen.  Perhaps the impact
> on engine speed happens so quickly that they need to pre-empt it by
> checking sooner?
>
> That board does not look too bad - no custom PLC or IC evident.  Those
> chips are just amplifiers http://www.futurlec.com/Linear/LM2902N.shtml
>
> Tom
>
>
>
>
> On Thu, Nov 14, 2013 at 2:09 PM, Neil N <musomuso@gmail.com> wrote:
>
>> This is a WAG but is it b/c the ICU is only using hall input as a
>> measure of a running engine and no more? And-or the ICU will react and
>> control the idle stab. valve faster using switches than it would using
>> engine RPM drop as a reference? Interesting question though.

--
Neil n

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