Date: Mon, 20 Jun 2011 13:48:22 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: '84 1.9L 2-WD -- cold start problems still the same after new
O2-sensor, new Temp II sensor, and new plugs
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reply-type=original
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
>>>>
>>>>
>>
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