[urq] Ideas for rough running continued - Solved!

[Ed Kellock]

I have those docs saved locally and would be happy to send them to you.

I wondered about the relationship between my adjustment and the
behavior of the cutout.   I had noticed a seeming relationship between
decel or closed throttle and the cutout previously while driving the
car.  However, immediatly after making the adjustment to the
distributor alignment, it was as if I could reproduce the cutout at
will.  There seems to be some relationship, I'm just not sure what it
is.

I'm not adverse to start replacing parts, but it sure seems like
there's something valuable to be learned from my sort of hollistic
approach at troubleshooting such that it might make any parts
replacements a bit more of an educated venture.

My adjustment to the distributor was minor and was not intended to
affect timing, it was intended to center the rotor better in the hall
sender window.  Currently, with all 3 engine timing references lined
up, the rotor is centered on the notch in the distributor body.  I
made sure that the window of mechanical slop is centered on the notch.

Ed

On Apr 7, 2005 7:06 AM, Ben Swann <benswann at comcast.net> wrote:
> I don't know if this will help, but as I am sorting out mine presently, have
> gleaned some information on the way things work with the WX engine.
> 
> One thing that you may not be aware of is that the idle control is done by
> advancing the timing which is different than on the later MC Turbo and the
> NA engines.  I don't recall there being an idle compensation valve/switch
> that lets more air in as the RPMs drop.
> 
> In any case, these events are triggered by the primary signal output by the
> hall sender - this signal/lead/wire goes directly to the F/TCU (Fuel Timing
> Control Unit) and processes  this signal  in conjunction with the Speed and
> Reference signals (flywheel sensors), Manifold Pressure, Coolant temp and
> air intake senders to advance and retard the timing..  The processed signal
> is output  to the fuel pump relay and Ignition Control Unit and presumably
> the tach.
> 
> By use of the Idle Switch located on the throttle body, the Idle Stabilizer
> Function of the F/TCU is switched on if the engine speed is below 820 RPM
> and the ignition timing advanced/retarded to regulate the idle speed.
> 
> Again, I haven't seen any reference to an idle air stabilizer valve like in
> many other cars, although there appears to be an auxiliary air valve -
> probably used during warmup and simply controlled by the thermo time switch,
> which is just an educated guess.
> 
> BTW adjusting the distributor will do nothing for the timing.  It is either
> "in window" or not.  Of course it is good to have the distributor set so
> that the hall windows are dead center, which would  be best should there be
> any slop in the mechnics of the distributor.  By using the two flywheel
> sensors in concert with the hall signal, the F/TCU knows exactly what the
> crank position is and the signals are synchronized.
> 
> Diagrams help to explain this and the best source are the two documents
> online "Audi Turbo Quattro Introductory.Service Training Information: and
> corresponding "Maintenance and Adjustments". These two documents will
> explain things far better than one ever could in an email.  Perhaps someone
> has these links - I lost all my links in a hard drive crash and am presently
> rebuilding them.
> 
> HTH
> 
> Ben
> 
> [Date: Wed, 6 Apr 2005 19:41:22 -0600
> From: "Ed Kellock" <ekellock at gmail.com>
> Subject: Re: [urq] Ideas for rough running continued - Solved!
> To: "UrqList" <urq at audifans.com>
> Message-ID: <000a01c53b12$e8fa6020$9f0a2146 at clspco.adelphia.net>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> I may have had an "AHA!" moment.
> 
> I went out the adjust the distributor subsequent to my weekend post
> and Ingo's response to see if anything changed with my ignition
> cutout.  It didn't.  The car started easily but sure enough the
> ignition cutout is still there.
> 
> As I sat there opening and closing the throttle, I noticed that the
> cutout seemed to occur as soon as I lifted my foot.  Once in a while
> it would happen a moment later as the rpms fell.  It did it reliably
> enough that I believe I can connect the behavior with the symptom.
> Not high rpm's involved, most of the time it was nothing over 2500.
> 
> When the ignition cuts out, the tach needle drops every time but the
> fuel gauge seems to be unaffected.  And the relay in the fuse panel
> that clicks doesn't do it every time, only when the duration of the
> cutout is longer.
> 
> What's the gizmo that holds the idle up a bit until the car warms, the
> idle control?  I think the temp sensor for mine is somewhat defective
> because the rad fan had already kicked on once before the idle control
> let the idle drop down to a more normal warm idle.  As soon as this
> occurred the cutout started happening by itself repeatedly but not
> necessarilly enough to kill the engine.  When I opened/closed the
> throttle to keep it running I found that I could reproduce the cutout
> much more directly always on decel or lift throttle.
> 
> Anyway, all of this reminded me of Ingo's sticking fuel plate spring.
> Now, maybe I'm pairing apples and oranges a bit here, but the
> similarity is interesting at very least.
> 
> Is there any relation between the lack of air flow and resulting fuel
> cutout as in Ingo's case and the ignition trigger?
> 
> Ed]
> 
>