[urq] intermittent ignition cutout

Sat Apr 9 18:02:37 EDT 2005

I just went out and tried this.  It didn't seem to have any effect on
the cutout.

----- Original Message ----- 
From: "Ingo Rautenberg" <irautenberg at comcast.net>
To: "Ed Kellock" <ekellock at adelphia.net>; <urq at audifans.com>
Sent: Saturday, April 09, 2005 3:13 PM
Subject: Re: [urq] intermittent ignition cutout

> Ed,
>
> You could check this fairly easily by plugging the vacuum hose that
goes to
> the ECU and see what happens with your easily repeatible Cut-out
situation
> by manually playing with the throttle.  If this changes things (like
no more
> ignition cut-out), then you may indeed have an ECU problem.
>
> Ingo
> ----- Original Message ----- 
> From: "Ed Kellock" <ekellock at adelphia.net>
> To: <urq at audifans.com>
> Sent: Saturday, April 09, 2005 5:08 PM
> Subject: Re: [urq] intermittent ignition cutout
>
>
> > What does the "decel valve" do?
> >
> > It has 3 connections, one goes to the turbo to throttle body hose,
another
> goes back to
> > the bottom of the intake manifold, and the 3rd is a smaller vacuum
line
> which goes to the
> > vacuum tree on the top of the intake manifold.
> >
> > I ask about its operation because this 3rd smaller hose is the one
which
> had the worst
> > vacuum leak that I fixed a couple of weeks ago when the ignition
cutout
> seemed to really
> > make itself known.
> >
> > The relevance that I'm wondering about is based on the assumption
that the
> smaller vacuum
> > hose to the decel valve is likely the trigger for its operation
and
> because the hose was
> > split at least half way around at the intake manifold fitting, I
figure
> the decel valve
> > wasn't previously doing much of what it was supposed to do.
> >
> > It seems fairly obvious that its purpose is to manipulate manifold
> pressure before and
> > after the throttle plate.  Yes, no, sorta kinda?  Does the decel
valve
> operate at all like
> > a bypass valve?
> >
> > Earlier today I began to wonder about the closed throttle, open
throttle
> nature relative
> > to my ignition cutout.  In addition to acutating the idle switch,
this
> activity also
> > causes manifold pressure to fluctuate.  I sat down and started
rereading
> the IST docs and
> > began to wonder about the pressure sensor in the ecu.  I was
pretty sure
> it has the
> > ability to affect ignition and I went back thru some old email and
found
> this from Dennis
> > below which states that the pressure sensor can cut ignition when
it
> thinks there's
> > overboost.
> >
> > It seems I may have discovered a possible tangible link between
opening
> and closing the
> > throttle and the ignition cutout.  I'm thinking it's a big maybe.
Anybody
> care to weigh
> > in on this?
> >
> > Ed
> >
> >
> > ----- Original Message ----- 
> > From: DGraber460 at aol.com
> > To: ekellock at adelphia.net ; urq at audifans.com
> > Sent: Wednesday, March 23, 2005 8:28 PM
> > Subject: Re: [urq] intermittent ignition cutout
> >
> > I'm purely shooting from the hip here, but my impression is that
the only
> true ignition
> > cut off these cars have is the over-boost pressure sensor in the
ECU, and
> oil pressure
> > loss? The pressure transducers do go bad once in a while from what
I hear.
> The load
> > reduction relay will not cut ignition- only lights and
accessories, and
> the fuel pump cut
> > off will not make the tach drop to 0.
> > I would try to pinch off the tube going to the ECU, eliminating
any input
> to the pressure
> > transducer, and see what happens.
> > The flywheel sensors are the only other "usual suspect" in my
thoughts. If
> the ECU can't
> > "see" TDC, it will cut spark. Why that would be heat related is
strange
> but could happen I
> > suppose. The sensors on the head will only make it run rich or
lean, but
> won't shut it
> > down.
> > Your car has taken on the early recalcitrant behavior mine showed
early
> on. Defying logic
> > and being somewhat of a bitch.
> > Have you swapped distributors with a known good unit yet?
> >
> > Dennis
> > Denver
> >
> >
> > In a message dated 3/22/2005 10:28:09 P.M. Mountain Standard Time,
> ekellock at adelphia.net
> > writes:
> >
> > Had hoped that my IC and burnt wire adventures would yield some
change to
> the cutout.
> > Still chasing the wire, so won't know for sure until its resolved.
> >
> > But, I've gotten a pretty clear fix on the behavior of the cutout,
purely
> subjectively of
> > course.  The cutout does appear to be temperature sensitive to
some
> degree, though not
> > summer heat temp type sensitivity.
> >
> > The car starts up beautifully and runs nicely as it warms, but as
it does,
> the cutout
> > manifests.  It's almost always momentary and as long as it's not a
idle
> (even sometimes if
> > it is), the cutout is short enough that the engine will catch and
continue
> running.
> >
> > I bought some resistors to put in place of a couple of sensors so
as to
> fake out the ecu
> > and either eliminate or isolate the issue.  In looking at the tdc
and rpm
> sensors, there
> > is a 3rd wire for ground.  I haven't quite sorted out how to rig
that to
> fake out the ecu.
> >
> > I have swapped in a spare ignition module (thanks Dennis!),
however the
> behavior was
> > unaffected.
> >
> > The cutout is definitely electrical in nature.  The tach drops to
zero and
> I think even
> > the fuel pump quits, though I'm not positive about that.  I
replaced the
> ignition switch
> > and the fuel pump relay about a year or 2 ago while diagnosing a
no-start
> situation.
> >
> > I've been wondering about the load reduction relay.  Mine appears
to be
> original.  I do
> > hear a click when the ignition cuts out.  Haven't been able to
isolate it
> yet though.
> >
> > Just a recap and thinking out loud.  I'm open to your thoughts.
> >
> > Ed
> >
> > _______________________________________________
> > Audifans urq mailing list
> > Send posts to: mailto:urq at audifans.com
> > Manage your list connection:
http://www.audifans.com/mailman/listinfo/urq
> > Have an urq question?  Check the Audifans Knowledgebase!
> > http://www.audi-quattro.org/cgi-bin/twiki/view/Audi/UrQuattro
> > Have an urq answer? ... Please help others by adding to the KB ...
all
> contributions welcome!
> >
> >
> > -- 
> > No virus found in this incoming message.
> > Checked by AVG Anti-Virus.
> > Version: 7.0.308 / Virus Database: 266.9.5 - Release Date:
4/7/2005
> >
> >
>
> _______________________________________________
> Audifans urq mailing list
> Send posts to: mailto:urq at audifans.com
> Manage your list connection:
http://www.audifans.com/mailman/listinfo/urq
> Have an urq question?  Check the Audifans Knowledgebase!
> http://www.audi-quattro.org/cgi-bin/twiki/view/Audi/UrQuattro
> Have an urq answer? ... Please help others by adding to the KB ...
all contributions welcome!