[s-cars] What to rule out before CPS (was fuel pressure tester port on AAN?)

Thu Apr 26 21:16:58 EDT 2007

Not to cast dispersions on the "it can't vapor lock" opinion, but I  
have had similar behavior earlier in the Spring when the weather got  
warm. We in Denver were still using "oxygenated" gasoline that has  
some 10% or so of alcohol. Alcohol has a much lower vapor pressure  
and will boil pretty easily, so I have ascribed the behavior to the  
alcohol. The reason I know it was lean, is that I have a full time  
TechEdge wideband A/F mixture ratio gauge, and it would read about 25  
or 30 while the engine was stumbling. I also have a very old fuel  
pump, and after about a minute of stumbling, the fuel system would  
settle down and everything would be fine. If you have an old fuel  
pump, it may be time to change. I know this doesn't exactly tie in  
with your 20 minutes of non start, but the "it started in September"  
might correspond to a change in gasoline composition.
FWIW
Mike Wakefield
93S4
97Cabriolet

On Apr 26, 2007, at 6:33 PM, Vincent Frégeac wrote:

> So my S-Bitch could have a slowly failing CPS. I'm still reluctant  
> to change
> it just to see for two reasons:
> - The warm start problem started back in September last year then
> disappeared because the temperature cooled down. So the CPS would  
> have been
> slowly failing for 8 months now. A bit long from what I've read on  
> the list.
> - The S-Bitch have a long history of making me R&R expensive parts  
> to then
> discover the problem was a very simple and cheap one to fix. I know  
> this
> argument is totally irrational but I'm as rational then this  
> argument when
> it comes to the S-Bitch.
>
> Now, there is still an argument in favor of the CPS. The S-bitch is  
> an old
> lady with 198Kmiles and CPS untouched since 70Kmiles when I bought  
> her.
>
> So before I unbury my wallet, is there anything else that I should  
> rule out
> before replacing the CPS? Symptom is S-Bitch doesn't want to start  
> within 20
> minutes after shut off when I've run at least half an hour on the  
> highway
> with outside temperature above 60F. Then it start as usual with a  
> somewhat
> uneven idling rpm sounding like a sticky ISV for a few seconds. Any  
> other
> time, highway below 60F, or less than 30 min. on highway, or city/ 
> country
> road driving, it starts fine but requires a few revolutions (3-5 rev.)
> before I hear the first spark plug firing gas.
>
> Any idea?
>
>
>
>
> Vincent.
>
> -----Message d'origine-----
> De : chris chambers [mailto:fastscirocco_2000 at yahoo.com]
> Envoyé : 26 avril 2007 13:39
> À : Vincent Frégeac; Scar
> Objet : Re: [s-cars] Fuel pressure tester port on AAN?
>
> Vincent,
>
> It can't be a vapor lock, with the fuel injection system it can't
> vapor lock.
>
> It sounds like an intermittent CPS. When the CPS fails the car
> will run but won't start. I had this same problem 2 years ago, when
> the car got warm it wouldn't restart, happened a few times and then
> the CPS failed completely.
>
> If your car has any amount of miles on it and hasn't had the CPS
> replaced I'd look there. Unfortunately there is no way to test the
> CPS other than replacing it.
>
> HTH good luck
> Chris
>
>
> --- Vincent Frégeac <s.sikss at gmail.com> wrote:
>
>> Hi,
>>
>> The S-Bitch has developed a annoying new behavior that looks like
>> vapor
>> lock, FPR or injector leak: she doesn't want to start again after a
>> long
>> stretch on the highway until you wait 15-30 min. depending the
>> temperature
>> outside.
>>
>> I found a fuel pressure tester on the net but doen't know if it will
>> work on
>> our fuel rail. It's said to have adapters for Chrisler, Ford, GM (who
>> cares?) and Bosch AFC but not Bosch CIS. IIRC, the CIS is the system
>> used in
>> the 80s on Audis, but what is the connection for the fuel pressure
>> test if
>> any on the AAN?
>>
>>
>>
>> Vincent
>>
>> -----Message d'origine-----
>> De : s-car-list-bounces at audifans.com
>> [mailto:s-car-list-bounces at audifans.com] De la part de
>> pkrasusky at ups.com
>> Envoyé : 25 avril 2007 14:23
>> À : s-car-list at audifans.com
>> Objet : [s-cars] NAC: trio comparo tittihardonarrro
>>
>>
>> Take 5 minutes and crank up the sound.  It unfortunately
>> conspicuously does
>> NOT include ME nor any JNR (tho my kids *did* violate the interior of
>> the
>> one from which I now don an ashtray).
>>
>> One of them induced sacshrinkage and resplendent gigglage here at the
>> 1-2 upshift - you decide which.  YEOWSERS!
>>
>>
> http://www.dpccars.com/car-videos/04-22-07page-Maserati-MC12- 
> Porsche-Carrera
>> -GT-Mercedes-McLaren-SLR.htm
>>
>> -Paul boingoingoingoingoingoingoingoing - hey - it's not an Audi! K.
>>
>>
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>
>
> Make April 15th just another day http://www.fairtax.org
>
>
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