Date: Thu, 29 Jan 2004 13:53:55 -0800
Reply-To: Damon Campbell <damoncampbellvw@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Damon Campbell <damoncampbellvw@YAHOO.COM>
Subject: Re: Weird bucking
In-Reply-To: <40197495.6020700@bellsouth.net>
Content-Type: text/plain; charset=us-ascii
This is an '84 with digijet injection... just the
simple idle stabilizer circuit... not your fancy
expensive one.
I did that a while ago, and don't remember there being
any change, but it is worth checking again, i suppose.
Thanks,
-Damon
--- John Rodgers <jh_rodgers@bellsouth.net> wrote:
> Warm the engine, remove the ISV connector, drive the
> vehicle. If the
> symptoms have disappeared, the problem is in the
> idle stabilizer
> circuit...either the ISV or the ISC. The ISC is
> nearly always the
> culprit. If you pull it and open it up, you most
> likely with find a
> burned resistor or capaciitor on the the circuit
> board. The ISC is in
> front of the right rear tail light. Remove the light
> to access the ISC.
> It just plugs in.
>
> Regards,
>
> John Rodgers
> 88 GL Driver
>
> Damon Campbell wrote:
>
> >In the last couple months, i've had a noticeable
> >low-speed driveability problem... kind of a
> >herky-jerky bucking at very light throttles.
> Happens
> >in any gear, but is more pronounced the lower a
> gear
> >you are in (1st being worst, 4th being not too
> bad).
> >This typically happens around 1500-2200 rpm, and
> kind
> >of comes and goes during a drive through town.
> >
> >I've had my trusty digitool on the dash looking for
> >any correlation, and there is nothing i can see
> from
> >any of the readouts. O2 is stable, AFM doesn't
> really
> >change at all, temp sensors doing their thing
> >normally... the only thing maybe kind of weird is
> that
> >i typically show a .06v ground potential difference
> >(since i have a digijet, my pin 19 is apparently a
> >ground reference, or something like that). This
> .06v
> >is always there, though, buck or not. This has
> >happened with two different ECUs, too.
> >
> >Now, i'm wondering if it could be possible that a
> >rebuilt tranny with clearances a little loose, a
> >specific clutch spring stiffness (actually have
> that
> >uber-LUK clutch bus-depot sells), a bigger motor,
> etc.
> >could all conspire to give a natural frequency at
> low
> >loads and certain rpms? This bucking, once it
> starts,
> >can be attenuated by either putting in the clutch,
> or
> >giving it a bit of gas... If the load and rpm are
> >just right, the bucking can build up to be quite
> >violent.
> >
> >How likely is this scenario? And if not, what
> would
> >some alternate theories be? The main two variables
> >include big engine and new clutch (had same rebuilt
> >tranny before new engine).
> >
> >As always, I appreciate all your thoughts on this,
> >-Damon
> >
> >=====
> >'84 Westy (Sparky) w/2.3L WBX (wow... it actually
> works!)
> >
> >__________________________________
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> >
> >
>
=====
'84 Westy (Sparky) w/2.3L WBX (wow... it actually works!)
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