[s-cars] ARGH!! Stalling at idle

[R. Mair]

sorry if i'm getting this problem mixed up with all the other diagnostic problems i deal with everyday. Cold start and cold run are two different problems. Anyway, the 02 sensor if heated will come online in short order, within 15-30 seconds after start-up. This could cause a problem if the sensor itself is shorted to ground, but not likely if it is simply lazy. Simple test here is to unplug the 02 sensor and see if the problem goes away or at least changes gretly. Same can be done with the MAF i believe. It works well on an OBD2 car, haven't tried it on OBD-1 but i can't see that it would be a whole lot different.

Rolf
  ----- Original Message ----- 
  From: Mark Strangways 
  To: R. Mair ; s-car-list at audifans.com 
  Sent: Friday, February 11, 2005 3:25 PM
  Subject: Re: [s-cars] ARGH!! Stalling at idle


  Quote:
  "I start my car in the morning and drive with little to no idling.  The
  symptoms are that when the car is cold and I get to a stop sign or
  red-light
  the RPM will dip more or less dependent on ambient temperature.  On cold
  days the engine will die.  I have replaced within the last 5K miles:"

  Doesn't sound like a cold start issue, sounds like I will not stay running 
  after it starts issue. Am I reading it wrong ?

  IMHO, after the ECU starts the car in open loop, off lookup tables, then it 
  will go into closed loop with or with-out o2 sensor feedback. A bad FPR is 
  certainly evil for that initial start, so are bigger injectors when not 
  coded right.
  Perhaps the O2 is done, or the MAF.
  These MAF's can result in some pretty weird problems when bad.
  Like I suggested before, find someone with a known good MAF and O2 sensor.
  Both are a 5 minute change out.

  Mark
  ----- Original Message ----- 
  From: "R. Mair" <waves at comcast.net>
  To: "Mark Strangways" <Strangconst at rogers.com>; <s-car-list at audifans.com>
  Sent: Friday, February 11, 2005 1:27 PM
  Subject: Re: [s-cars] ARGH!! Stalling at idle


  FPR can cause cold start problems, but as you noted, it will be backed up by 
  problems in other areas. Marks problem seems to only be cold starts. After a 
  few minutes everything seems normal. FPR, when bad, will not be selective 
  about only one facet of a drive cycle, unless you have a very very rare 
  issue. If it favors lean, it will always stay lean. Same goes for Rich. If 
  mark was having trouble with cold starts, and the FPR was at fault, then he 
  would likely also notice a lack of power or a miss at WOT. If the FPR sways 
  rich, it will start OK but will go through fuel and will be noticed at the 
  pumps when you have to fill up more frequently,among other things like black 
  smoke and lopey idle. My initial post was that given the exact problems mark 
  spoke of, the FPR cannot be the problem alone. Given your problems however, 
  i can see where the FPR would be an issue.

  Rolf

    ----- Original Message ----- 
    From: Mark Strangways
    To: RM ; s-car-list at audifans.com
    Sent: Thursday, February 10, 2005 8:31 PM
    Subject: Re: [s-cars] ARGH!! Stalling at idle


    Well, with out starting another war, I am going to disagree with you.
    In my case, maybe only my case, I had (through my own intervention) a very
    sick little FPR. It caused all sorts of strange little issues.
    Cold starts where a BITCH.
    Warm starts where and where not problems, depended on the day.
    Yet, WOT would run SOOOOO rich, it looked like a diesel.

    I am NOT saying that this is Marks problem, but it should be easy enough 
  to
    check the running pressure, and bleed down after shut down.

    And that is all I gots to say on this one.

    Mark (not wanting a contract) S
    ----- Original Message ----- 
    From: "RM" <waves at epix.net>
    To: <s-car-list at audifans.com>
    Sent: Thursday, March 10, 2005 11:10 AM
    Subject: Re: [s-cars] ARGH!! Stalling at idle


    >
    > Mark, no matter what anyone says, fuel pressure is not the issue here. 
  FP
    > is vacuum adjusted, not temp. driven. Yes, in effect the FP reg. could 
  be
    > bad, but it would affect more than just cold starts. The CTS is the
    > leading input to the ECM for cold starts. Check here first. Having said
    > all this, your 95.5 is possibly OBD-2 compliant and requires proper
    > experience, info systems and tools to diagnose correctly. Most anyone 
  can
    > visually look for problems (broken vacuum lines or hoses) and most
    > everyone can replace sensors and switches out of frustration. I have at 
  my
    > disposal the real factory info system and thousands of $$$ of quality
    > diagnostic tools, and i still can find difficulty finding problems, esp.
    > with older cars that have a few miles on them. Unless this is a common
    > problem with these cars, which it isn't all that common, you'll be 
  subject
    > to allot of specualtion and that could cost you more than if you took it
    > to a trusted technician.
    >> Rolf Mair
    >> waves at epix.net
    >>
    >> 94 UrS4
    >> 90 20v turbo 90q
    >> 69 camaro conv.
    >> 02 Allroad (wifes)
    >>
    >
    >
    >
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