Hard start, cold start problem, rough idle

[Derek Pulvino]

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
>>
>>
>>