[urq] suddenly lean again

[SpotatAshleys]

Hi Frank
 At the moment I am going with Ado's suggestion but can't get near the car
at the moment for  rain. (I know what you're thinking...where's his
dedication to duty?) Well gone are the days when I worked in all weathers.
I've got soft. As soon as it stops raining and it's daylight I'll have a
look at it and will report back to the list.
I too wondered if it was simply the turbo stalling as the throttle slaps
shut but reckon this would not cause the mixture to go lean like it is. I
would expect the opposite to happen if the turbo stalled or am I mistaken?
But then if the turbo stalled, why does the mixture return to rich if I lift
off and reapply the throttle, the revs are still low nothing has changed
except the mixture? Mmmm.
I'll see what the situation is with the switches and solenoid first and go
from there.

Many thanks

Keith
----- Original Message -----
From: "fdekat" <fdekat at sentex.net>
To: <urq at audifans.com>
Sent: Tuesday, January 09, 2007 2:04 PM
Subject: [urq] suddenly lean again


> >  Sometime last year I had a problem that I asked for help on but I
> > regretfully did not keep the replies and the problem went away and I
> > never found out a cause. Well it has started again. The symptoms are as
> > follows:
> >
> > If I accellerate hard in any gear it pulls like a train and the air fuel
> > meter shows (as expected and desired) a rich mixture. When I lift off ,
> > change up and re-apply the accellerator the power has gone and the
> > mixture has gone lean. If I were to keep my foot down this condition
> > would remain. If I lift off and then reapply the accellerator then the
> > power returns, the mixture returns to rich and it would  continue to
> > pull until I ran out of revs. If I keep my foot down instead of changing
> > up the mixture remains rich so it does not appear to be a case of fuel
> > starvation.
>
> I've had a similar problem, but I have no air fuel meter so never noticed
a
> mixture change. I noticed the problem with the same lack of power
symptoms.
>
> Pulling hard, upshift (with quick close of throttle), then back on the
> throttle hard, and NO power.  Interesting enough though, boost gauge still
> showed plety of boost pressue when this happens, but still no power.
>
> But put in clutch, rev motor, let out clutch, and now lots of power.
>
> I put it down to the turbo being 'unspooled', and changed my shifting
> technique so that I keep the throttle partly depressed when shifting, and
not
> 'snapping' it closed. (Although plenty of boost makes that 'unspooled'
theory
> suspect).
>
> Unrelated, I have changed from the original ECU to a complete MAC11 system
> (harness, ECU and all related bits), wihile retaining the stock urq fuel
> metering unit.  Throttle switches tested operational to the ECU connector.
>
> No change!  So makes me think the problem may be something about the fuel
> metering unit.
>
> I too will be interested in what your solution is!
>
> Regards,
>
> =Frank de Kat=
>
>
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