Now hot idle problem

[Tex Terry, II]

Matt - Have you changed your air cleaner?  Have you checked the injectors? 
Have you checked the fuel distributor adjustments?  Your problem sounds
like an air/fuel mixture problem.  If you are running rich (too much fuel
for the amount of air at the moment) then when you give it "more throttle"
you are actually giving it more air to mix with the extra fuel.  At idle,
the fuel may be controlled well enough to work with the amount of air, but
when you are running at higher rpms, and therefore providing more fuel, you
need more air, which you are getting when moving.  But for the few moments
that you are letting off the throttle to slow down, you have less air, but
apparently you are still providing extra fuel (for that particular
situation) so you run too rich and the engine finally wants to die.  Just a
suggestion of where to start checking.

Tex Terry, II
83 5kt

> Message: 9
> From: "Matt Beaubien" <mrbeau0 at yahoo.com>
> To: <quattro at audifans.com>
> Subject: Re: Now hot idle problem
> Date: Tue, 26 Jun 2001 23:28:09 -0400
> 
> It started doing it again on the way home from work.  The only way I
could
> get it to idle was to give a good bit of throttle.  It wants to die when
> shifting gears, and will die if left in neutral long enough.  Drivability
is
> actually ok, and it pulls just great at 1.4/1.5 bar.
> 
> I grabbed some dinner after work, and then went to work on the car some
> more.  Of course I can't replicate the problem.  I let it idle for 15
> minutes and nothing happened.  I heat soaked it for a bit and let it idle
> some more.  Nothing happened.  I drove it around for 5 minutes and
nothing
> happened again.  Ugh.  I tried disconnecting the throttle switch and it
> didn't do what it was doing before.
> 
> My thought is that it is something electrical.  It wasn't as warm after
work
> as it was during the day, and I didn't have this problem a week ago when
it
> was cooler.  It reminds me of my flaky fuel pump relay that would make
the
> car run crappy at the _exact_ same point on the drive home.  Flaky
> electrical devices seem to be affected by a time at temperature
situation.
> Sounds much like what I'm experiencing now.
> 
> So, what's electrical and affects the idle air and/or fuel.  I can pretty
> much guarantee it's running lean when this happens, though it could be
> ignition.
> 
> Place your bets now!
> 
> TIA,
> 
> Matt Beaubien
> '86 5kt
> '73 911E
> 
> ----- Original Message -----
> From: "Matt Beaubien" <mrbeau0 at yahoo.com>
> To: <quattro at audifans.com>
> Sent: Tuesday, June 26, 2001 1:02 PM
> Subject: Now hot idle problem
> 
> 
> > I still have my cold-start problem (unrelated, it's
> > been around for months), but yesterday I suddenly
> > developed a hot-idle problem.  I was coasting to a
> > stop in neutral when I noticed the brake pedal was a
> > bit stiff.  I glanced down at the dash and noticed
> > that the dash lights were on and the tach was at zero.
> >  I cranked a bit and it fired back up.  This happened
> > a few more times.  I poked around the engine bay and
> > didn't see anything really amiss.
> >
> > I unplugged the O2 feedback to see if that would have
> > any effect.  It seems to be about the same.  No
> > obvious air intake leaks, though I don't no if they
> > would cause a problem when hot.  The ambient is a bit
> > hotter than it has been (~80F), but it was this warm
> > ealier and didn't have any problems.
> >
> > New parts: fuel pump, MM hose, plugs, wires etc.
> >
> > It sure seems like it's running lean when it starts to
> > miss.  I'll try monitoring the O2 signal when it's
> > running but not missing.
> >
> > Any idea on why it's fine when cold?  Cold would be
> > <~85C on the coolant temp.  Once it's warm enough for
> > the fan to kick on is when I seem to have problems.
> >
> > Thanks (again) in advance,
> >
> > Matt Beaubien
> > '86 5kt
> > '73 911E
>