Surging Issue... at idle and when driving. arghh.

[Andrew Dickinson]

I am wondering, that because the ECU was moved from the stock location,
if they connected to the vac lines for door locks and the like.

Hayes, if you have found the ECU why don't you try disconnecting the
vac/boost line from the ECU The ECU should see atmospheric pressure then
and that will be indicated by a 0.9 or 1.0 on the dash.  In fact, when
you turn the car 'on' (before hitting the starter) it should read that
value too as it should only see vac after the car has started.

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com]
On Behalf Of urq
Sent: March 18, 2009 2:44 AM
To: quattro at audifans.com
Subject: RE: Surging Issue... at idle and when driving. arghh.

... if you are seeing a constant manifold pressure reported it indicates
that the pressure transducer in the ECU isn't working ... that or
there's a
manifold pressure plumbing issue ... but it would be hard to figure out
a
way to hook things up to wind up with a constant partial vacuum ... 

Steve B
San Jose, CA (USA)

-----Original Message-----

It almost sounds like a dying fuel pump too.

One strange thing with this car is that the dash always shows a pressure
of 0.4bar vac.

-----Original Message-----

Hayes Myers wrote:
> Was having some cold starting issues (wouldn't hold idle and would
stall
> sometimes).   Put in replacement ISV and all was well again... been
just
> over a week since putting isv in .   Just now car started to 'surge'.
it
> will idle up and down rapidly at the lights... and will surge even
> driving... up/down up/down.  WHen you upshift the revs were not
dropping
> recently (ie: seemed to be 500rpm too high...revs didn't fall off)...
now
> they actually increase.

If your car has an idle switch, check to make sure it's still working. 
If it isn't (ie, staying "open"), your ECU won't know when to use the 
ISV to make a smooth idle.

Although, this doesn't address the surging while driving...

-- 
Huw Powell

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