How much of a vacuum leak will be caused by old vent lines on top of
fuel tank?  If those vent lines are bad, would not that create a vacuum
leak just as much as a leak in another vacuum line?

John

On Mon, 2011-06-20 at 13:48 -0700, Scott Daniel - Turbovans wrote:
> hi..
> no..a 'cold start valve' is a '5th injector' ..
> used on fuel injection systems prior to Digijet  and Digifant.
> CIS fuel injection cars use them ..
> air-cooled Vanagons have them ..
> but not our waterboxer vanagons.
>
> the Aux Air valve can affect idle...
> It is basically a temp-controlled air valve that increases cold idle speed
> by routing air around the throttle plate.
> in my experience  they all seem pretty 'sleepy' these days..
> like they do not seem to increase cold idle speed much at all.
>
>  I won't say 'it just can not be the aux air valve' causing hard starting,
> but I will say that the part itself is unlikely to cause hard cold starting.
>
> and ..of course, if any hoses are off or anything like that ..
> that could affect cold starting ..but it would also show up as an idle
> problem warm, most likely.
>
> scott
> ----- Original Message -----
> From: "pickle vanagon" <greenvanagon@GMAIL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Monday, June 20, 2011 1:05 PM
> Subject: Re: '84 1.9L 2-WD -- cold start problems still the same after new
> O2-sensor, new Temp II sensor, and new plugs
>
>
> > really??
> > I think the whole purpose of the aux valve is to make cold starting
> > possible.  (I think they're even sometimes called cold-start valves).
> >
> > The idle screw setting appropriate for a warmed up engine is not enough
> > for
> > a completely cold one.  This is where the valve comes in, unless I'm
> > mistaken.
> >
> > If the valve is stuck shut, I would definitely expect it to impact cold
> > starting.
> >
> >
> > On Mon, Jun 20, 2011 at 3:36 PM, Scott Daniel - Turbovans <
> > scottdaniel@turbovans.com> wrote:
> >
> >> Aux air valve shouldn't have much to do with cold starting ..
> >> unless the hoses to it are off or something like that.
> >>
> >>
> >> ----- Original Message ----- From: "pickle vanagon" <
> >> greenvanagon@GMAIL.COM>
> >> To: <vanagon@GERRY.VANAGON.COM>
> >> Sent: Sunday, June 19, 2011 3:14 PM
> >> Subject: Re: '84 1.9L 2-WD -- cold start problems still the same after
> >> new
> >> O2-sensor, new Temp II sensor, and new plugs
> >>
> >>
> >>
> >>  The only other thing that comes to mind is the aux air valve.
> >>>
> >>> This is the little valve that is supposed to be open when the engine is
> >>> cold
> >>> letting in extra air, and then close as it warms up.  It has a plug that
> >>> goes into it as well, that powers a heating element.
> >>>
> >>> The spring in yours might be worn out, or maybe the valve "door" itself
> >>> is
> >>> gunked up and stuck in place.
> >>>
> >>> I don't think these can be purchased new anymore in the Vanagon part
> >>> number,
> >>> but I think they are interchangeable across old VWs (jettas, busses,
> >>> whatever).  [warning: I'm embarrassed to say that I know from experience
> >>> that it is easy to overtighten the locking nut on the the adjustment
> >>> screw
> >>> and break off the screw.]
> >>>
> >>>
> >>> But, on the other hand, your aux air valve could be fine, in which case
> >>> this
> >>> is going to add another variable that you'll be fiddling with trying to
> >>> get
> >>> in the right balance with the idle screw setting.
> >>>
> >>> Good luck!
> >>>
> >>> On Sat, Jun 18, 2011 at 12:43 PM, John Lauterbach <
> >>> jhlauterbach@bellsouth.net> wrote:
> >>>
> >>>  Cold start problem definition:  Engine temperature and air temperature
> >>>> around 70-75 degrees Fahrenheit.  Start engine w/o foot on accelerator
> >>>> pedal.  Engine starts and goes to around 800 rpm (instrument panel
> >>>> tachometer).  If slight pressure put on accelerator pedal to take rpm
> >>>> to
> >>>> 1500 or so, and then pedal released, rpm drops to around 300 and engine
> >>>> tried to stall and then picks up speed and then tries to stall.  Slight
> >>>> pressure on accelerator pedal for a couple of minutes or so, solves the
> >>>> problem.
> >>>>
> >>>> Here is what I have done:  New within the past two weeks are new
> >>>> O2-sensor, new Temp II sensor, and new plugs.  A couple of months ago,
> >>>> I
> >>>> put in new rotor and cap.  Timing is just ahead of the mark.  I am also
> >>>> working with backup ECU and I have cleaned the contacts on large cable
> >>>> going into ECU.  I have checked for vacuum leaks and replaced suspect
> >>>> hoses and fittings.
> >>>>
> >>>> Engine is Boston Bob rebuild that I installed in September 2003.  Has
> >>>> about 40,000 km on odometer.  Just about everything I could buy
> >>>> new/rebuilt at that time such as distributor and AFM went was replaced
> >>>> at that time.  A few years ago, I installed a rebuilt throttle body.
> >>>>
> >>>> Recommendations on next steps would be appreciated.
> >>>>
> >>>> John
> >>>>
> >>>>
> >>