Skip to main content
Gerry | Vanagon
Checking account...
← vanagon.com home · Continue the discussion in the forum
Subject:Re: '84 1.9L 2-WD -- cold start problems still the same after new O2-sensor, new Temp II sensor, and new plugs
From:pickle vanagon
Date:Mon, 20 Jun 2011 16:05:41 -0400

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
>>>
>>>
>