boost back off...was Re: [s-cars] Fuel mileage questions

[Bill Clancy]

Jason Butler wrote:
-- It seems like it gets good boost then the ecu backs off just a little
then lets the boost go again.


Mine does that too.  (95 S6).   Sometimes I have to wait for the full boost
to come back on again, sometimes I never get all the power.    Is it
supposed to do any of that?    Does anyone know how to fix that feature so
that one can get all of the power all of the time?    To add another detail,
I notice that I can usually get full power if I stomp on the gas while the
engine is already at 4000 rpm.   But if I step on it with the engine at,
let's say 2800 rpm, I may or may not get the power I want thru the entire
range -- but sometimes if I wait, it will finally kick in at 5000 and run
strong all the way to red-line.

It seems like mine has something wrong with it, but it doesn't happen all
the time.   Has anyone had this sort of problem.

BTW, I just took a 1000 mile highway trip.  I got 21 MPG.    Around town
(with lots of stops and hills) I can get as low as 12 mpg.

-Bill



----- Original Message ----- 
From: "Jason Butler" <jwbutler at wispertel.net>
To: "chris chambers" <fastscirocco_2000 at yahoo.com>;
<s-car-list at audifans.com>
Sent: Friday, March 04, 2005 9:24 AM
Subject: Re: [s-cars] Fuel mileage questions


As far as O2 sensor I get no black smoke that I can tell.  I do get a
subtle surging when I am under boost.  It seems like it gets good boost
then the ecu backs off just a little then lets the boost go again.  I have
a 93 which doesn't have the little computer in the dash for avg mpg or
boost ect...  And I haven't gotten a boost gauge in yet.

As for temperature it seems to be good.  I run right at the middle mark
consistently.

I have looked at the air filer and it is very clean.  Although it is just a
paper filter.

Have not checked fuel filter yet.

Jason

At 10:07 AM 3/4/2005, chris chambers wrote:
>Jason,
>
>Your mileage sounds low, I average 22+ mpg with my RS2 mods.
>Check and consider replacing your Air filter, Fuel filter and O2
>sensor.
>
>A bad O2 sensor can easily cause increased fuel consumption, this also
>normally include some amount of black smoke.
>
>Also I have read that a thermostat that has failed and is stuck open
>will keep the engine from warming up and can caue an increase in fuel
>consumption. Does your engine warm up fully?
>
>
>HTH
>Chris
>
>
>
>--- Jason Butler <jwbutler at wispertel.net> wrote:
> > I have owned my 93 S4 for 3 months now and am wondering what kind of
> > fuel
> > mileage is normal.  I have been getting around 18 mpg which includes
> > quite
> > a bit of city driving and about 40 miles a day of highway driving.
> > With
> > gas prices going up so much here in Denver I would like to maximize
> > my
> > mileage.  the S4 is completely stock with 180K miles on it.  Any
> > thoughts
> > on what will maximize mileage?  I don't drive it too hard because I
> > know
> > when you get into high boost it sucks gas.
> >
> > Thanks
> > Jason
> > 93 S4
> > 91 90 Quattro 20v
> > 90 Coupe Quattro (parting out)
> > 86 5ktq
> >
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> >
>
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