Hard start, cold start problem, rough idle

Thu Jun 29 19:05:21 EDT 2006

Bernie,

Replaced the 02 sensor about a year and maybe 15k-miles ago, and have not 
reason to think my splices were bad.

Heater core wasn't too bad...or as bad as everybody made it out to be.  I 
think some of the heavy "cautionary notes" I got made me proceed a little 
more conservatively than I otherwise would have.  For example, everybody 
said "take good notes before you take apart the heater box."  Well, putting 
that together wasn't that difficult.

The biggest problems?  Putting all the stupid little trim/hose/plenum pieces 
back together once resintalled, finding a decent way to seal the hoses with 
common household goods when I pulled the assembly out, and deciding to use a 
silicon high temperature gasket maker to reseal the heater core. The silicon 
crap is still off-gassing a "pleasing" vinegar like smell.

Derek P

>Derek, Bryan, and others with this problem.
>
>Obliviously there could be multiple causes for these symptoms, but 
>replacing
>the O2 sensor solved the problem on my 90Q-20V.
>
>Good luck, and Derek, how did the heater core go? Takes lots of beer and
>vocabulary for that one.
>
>Bernie
>
> > From: "Derek Pulvino" <dbpulvino at hotmail.com>
> > Date: Thu, 29 Jun 2006 13:46:47 -0700
> > To: brfoster at gmail.com
> > Cc: 200q20v at audifans.com
> > Subject: Re: Hard start, cold start problem, rough idle
> >
> > Bryan,
> >
> > It's a possiblity, but only way to know is to pull out the injectors and
> > check things out.  I also know on my car that on start up, I do get
> > excessive smoke and that could be from bad valve stem seals, but the 
>smoke
> > (when I back through it) always has more of a burnt gas than oil
> > smell....further reinforcing the "too much gas" theory.
> >
> > On my car, the rough running doesn't last for 10-minutes...the inability 
>of
> > the car to idle w/out my foot on the gas when warm does.  Usually rough
> > running goes away after a minute or so...although yesterday it carried 
>on
> > for a couple of minutes.
> >
> > Derek P
> >
> >> Thanks Derek,
> >> What do you think of a single isolated leaky injector?  If the car was
> >> sitting for at least 30min it could accumulate enough leaked fuel into 
>the
> >> cylinder causing an overly rich mixture on startup - giving a rough 
>idle at
> >> startup only.  I dont know why that would last up to 10min in your car
> >> however.  It seems to fit my problem of 30-45 sec more.
> >>
> >> Bryan
> >>
> >>
> >> On 6/29/06, Derek Pulvino <dbpulvino at hotmail.com> wrote:
> >>>
> >>> Bryan,
> >>>
> >>> I've been having the same problem for a while, and notice it also does 
>go
> >>> away in the colder months...in fact now that's it's warmer again, when 
>I
> >>> restart my car when it's warm, and last ran within an hour to two, the 
>car
> >>> won't idle at all without me keeping my foot on the gas...that 
>condition
> >>> lasts for at least 10-minutes.  Also notice the rough running when I
> >>> restart
> >>> the car, lot of stumbling for a couple of minutes and the check engine
> >>> light
> >>> will come on, but I get no fault codes.
> >>>
> >>> Right now, my key suspect is the idle stabilizer valve, and I do 
>recall
> >>> that
> >>> when I last pulled it to check, the flapper/valve seemed to
> >>> immovable.  Was
> >>> going to do an "output test" when I get some spare moments again.  The
> >>> only
> >>> thing I can think is maybe this is sticking, and causing the car to be
> >>> overly rich on warm startup...but it doesn't answer the question as 
>the
> >>> why
> >>> the car wouldn't also do the same once it's warmed up.
> >>>
> >>> Some other ideas I had was maybe the temp. sensor to the ECU was 
>crapped
> >>> out, but resistance at the sensor was within spec when I checked, or 
>maybe
> >>> I've got a back check valve which is letting the fuel pressure decline 
>too
> >>> much between starting...but then I wouldn't have idle problems for as 
>long
> >>> as I do.
> >>>
> >>> All in all, this is quite frustrating and not contributing to a health
> >>> demeanor when I'm on the road.
> >>>
> >>> Derek P
> >>>
> >>> Message: 1
> >>> Date: Wed, 28 Jun 2006 17:05:45 -0400
> >>> From: "Bryan Foster" <brfoster at gmail.com>
> >>> Subject: Hard start, cold start problem, rough idle
> >>> To: 200q20v at audifans.com
> >>> Message-ID:
> >>> <9be3f0980606281405v257c1184q199efc0a6c4b9464 at mail.gmail.com>
> >>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >>>
> >>> Listers,
> >>> I have had a couple of weeks of rough idle during cold start ups.  The 
>car
> >>> will start easily, but then idle very roughly for 30-45sec.  After 
>that
> >>> time
> >>> it runs and idles very smoothly.  If I start it up and immediately rev 
>the
> >>> engine to >2000rpm then it runs very smoothly, but if I was to let off 
>the
> >>> gas and let the engine slow down to idle then it sputters and nearly
> >>> stalls.  When I rev it up right after start up there is a considerable
> >>> delay btw putting my foot down and engine response as if the mixture 
>is
> >>> way
> >>> off.   It seems to happen if the car has been sitting for >1 hour.  
>Not
> >>> necessarily a completely cold block.  Does this point to anything in
> >>> particular.  Leaky injector?
> >>>
> >>> Thanks in advance,
> >>> Bryan Foster
> >>>
> >>>
> >>>
> >
> >
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