Date:         Wed, 23 Sep 2020 16:54:07 -0400
Reply-To:     alex@MEVAY.ORG
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Alex MeVay <alex@MEVAY.ORG>
Subject:      Re: '81 air-cooled engine stall (increase idle speed)
Comments: To: al sinclair <alvanagon@gmail.com>
In-Reply-To:  <CAMfb+V81u35PiEert65ydHQnMQwtr4P_ythifDM3QNpkocEcfg@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

Hi Alan,

What engine management do you have?  Is it Digifant II?

I've been trying to solve a similar or identical issue in my van
(hesitation/misfire on abrupt throttle application).  Apparently
vacuum lines or other unmetered air leaks are a common cause.  I've
been through that, all the usual tuneup stuff, swapping AFM's,
DigiFAST chip, all without much improvement.  My next idea is that
maybe it's a fuel supply issue.  Clogged fuel filter, worn pump,
sticking pressure regulator, etc. that allows the fuel pressure to
drop too much or for too long on initial acceleration, leading to a
lean misfire.  I'll post if I get to the bottom of it, but I'm also
interested in other suggestions on this issue.

Alex





On Wed, Sep 23, 2020 at 4:17 PM al sinclair <alvanagon@gmail.com> wrote:
>
> Our '81 Vanagon (automatic transmission) tends to stall on accelerating
> from idle, e.g moving off after sitting at a stop light. It's fine if I
> keep the idle speed up a little with my foot on the accelerator. And while
> moving there's a hesitation for well over a second when pressing the
> accelerator after coasting before engine power kicks in - likely the same
> issue.
>
> Is there another way to increase the idle speed besides turning the "idle
> speed adjusting screw" (Bentley page 24.23)? turning that makes no
> difference to the idle speed. I realize that's not addressing the actual
> problem (of course it would be better to solve it) but increased idle speed
> would avoid the stalls.
>
> Any clues to solving the underlying issue would be great too, but I need to
> eliminate the stalls so my wife can drive the car.
>
> This is a different issue, because it's happened for years and the stall
> issue is new, but noting it in case it's relevant: at speed if the
> accelerator is pushed to the floor the engine hesitates, and only picks up
> if I back off the throttle.
>
> thanks
> Alan