[V6-12v] Almost stall at start

[The CyberPoet]

I would imagine that either:
(A) The external temp sensor is off (thinking the air is thicker than  
it is, leaning down the mix until the O2 sensor protests), OR
(B) There is a minor vacuum leak somewhere that it ends up  
compensating for... OR
(C) dirty injectors, again until the O2 sensor protests (which can be  
easily cleaned by putting them in an ultrasonic cleaner overnight  
with some fuel system cleaner; be sure to only use the type of  
ultrasonic cleaner that doesn't generate heat in the fluid when  
vibrating).

But those are strictly SWAGS.

Cheers
=-= Marc

On Feb 24, 2006, at 8:38 AM, Lino M. Valadas wrote:

> Hi,
>
> My wife's 93 90cs has for a long time experience the following at  
> start up
> time:  The engine starts always very well with no gas, revs up and  
> then
> within a few seconds the revs come to almost stalling.  At that  
> point some
> other mechanism kicks in and bring the engine back up to normal idling
> speed.  The engine never really stalls.  Once it does this hiccup,  
> it never
> does it again until the next cold start.  I have cleaned the ISV to no
> avail.  Has anybody experience this?  Is there a sensor sending the  
> ECU the
> wrong input? Any suggestions would be welcome.
>
> TIA
> Lino
>
>
> ----- Original Message -----
> From: "Rob" <beattyr2003 at cox.net>
> To: <V6-12v at audifans.com>
> Sent: Saturday, January 28, 2006 7:11 PM
> Subject: [V6-12v] New A6 with some minor issues and some questions
>
>
>> So I made the leap from 200 tq to the A6Q.  I love the car, but  
>> certainly
>> miss the acceleration of the 200.  Have some minor things to work out
>> though.
>>
>>
>>
>> Car is a 1995 A6 Quattro sedan with manual transmission.  The AC  
>> head fan
>> speed display light is blown out.  I also am not getting airflow  
>> through
> the
>> footwell vents.  I haven't run the diagnostics yet, have to read  
>> through
>> them, and its from an online tech site, not from the factory  
>> manual, so it
>> takes some reading and re-reading to be sure of what they mean.   
>> It also
>> looks like I can diagnose those problems without a Vag 1551, at  
>> least I
>> think so.
>>
>>
>>
>> Also having come from the 200 platform up to the A6, this is my first
>> exploration of OBD and OBD II.  I know one needs either the Vag  
>> 1551 or
> Vag
>> Com or another variant of the software for diagnosing fault  
>> codes.  How
> hard
>> is it to make the adapter cable for the serial port?  I am skilled in
>> electronics and have plenty of experience fabricating cables, I  
>> just need
> to
>> know what I am connecting to.  Anyone have a pinout of the DB9  
>> (serial
> port)
>> connector to the connections for the diagnostics?
>>
>>
>>
>> Other issues the car is having is intermittent check engine light  
>> under
>> partial throttle.  EGR system is suspect, I need to run the test  
>> of that
>> system and clean it out also, probably its just carbon build up.
>>
>>
>>
>> Otherwise, I love the car, and the wife loves her 95 A6 wagon that we
> bought
>> about a month earlier, though I'm still jonesing for the S6  
>> instead heh.
>>
>>
>>
>> Thanks,
>>
>>
>>
>> Rob
>>
>>
>>
>>
>>
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>
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