Date:         Fri, 7 May 2010 12:55:35 -0700
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: Analog to Digital Idle Stabilizer Control
In-Reply-To:  <4BE437FC.4080701@charter.net>
Content-Type: text/plain; charset=ISO-8859-1

> My apologies - but I can never remember who is was/is working on a
> digital replacement for the analog box just forward of the right hand
> tail light.
>
> Anyone know what has become of that project?
>
>
That's me! I'm still plugging away at it as time permits. I have a test unit
that can open the idle valve between 0 and 100%, but it doesn't have fine
enough control. Idle jumps erratically from "nearly stalling" to "headed for
red-line". I suspect the pulse width modulator built into the Atmel
controller I'm using just doesn't work at a frequency the solenoid valve
likes. Subsequently, I have to write a PWM routine myself from scratch--- a
task I've been procrastinating on because it doesn't sound fun. The biggest
problem is going to be to figure out what frequency WILL work. Trial and
error is pretty tedious. I've been poking around for an oscilloscope so I
can measure what the stock analog unit operates at, but nothing affordable
has showed up yet.

Still, my spare idle valve and the controller unit are always sitting front
and center on my desk at home, and I do fiddle with it at least a couple
times a week.

--
John Bange