system pressure leakdown

[Jon Boyer]

Still sounds like the WR regulator is not working correctly.  The lack of
power is probably a lean engine (danger).  Try the swap and see what
difference that makes.

best of luck!

JB


>From: Ben Swann <bswann at worldnet.att.net>
>Reply-To: "bswann at worldnet.att.net" <bswann at worldnet.att.net>
>To: 'Ben Swann' <bswann at worldnet.att.net>, 'Graham Thackrah'
><gthack at geog.ucl.ac.uk>, 'Jon Boyer' <jonboyer at hotmail.com>
>CC: "'quattro at audifans.com'" <quattro at audifans.com>,
>"'quattro at isham-research.com'" <quattro at isham-research.com>
>Subject: RE: system pressure leakdown
>Date: Tue, 16 Apr 2002 20:13:41 -0400
>
>I disassembled the Warmup/Fuel Pressure Regulator(FPR) and cleaned the
>metal diaphram - it really didn't look bad.  Back together, made maybe a
>little difference.
>
>Part of the problem that crept into the works was actually my guage set
>misbehaving.  That must have happened right about the time I put new
>o-rings in the check valve.  Anyway, swapped check valves between the two
>avants with no difference in either car, so I rule that out.  Pulled the
>guages out, and was able to get the car to idle fine when adjusted slightly
>rich, such that the frequency valve is not activating at idle.  So the
>guages were messing me up, causing me to think I did something wrong when I
>replaced the o-rings in the check valve.
>
>Now, however, it seems to fall flat around 4000-5000 RPM - was pulling
>easily to 6500 the other day, just started and idled poorly.
>
>So the problems I still have  are:
>1) Poor starting  cold and even after setting 10 min.
>2) Loss of power as if mixture is off.  Sometimes it pulls great, and
>sometime it doesn't.
>
>I am still pretty sure the problem is in the fuel delivery.  I guess I need
>some new guages, and to re-test.  Perhaps swapping the Warmup/FPR with the
>other car will rule that in or out.
>
>Anyway, the car runs OK enough to use, but I'm troubled now, after all of
>this work so far.
>
>Ben
>
>On Tuesday, April 16, 2002 1:07 PM, Ben Swann
>[SMTP:bswann at worldnet.att.net] wrote:
> > Graham.,
> >
> > No, not too late as I am still having problems.
> >
> > Perhaps total leakdown both control and system sides is normal, but
>there
>was something seemingly flaky going on with the control pressure.
> >
> > I wanted to verify system check valve not leaking, which Probst alludes
>to checking first.
> > I put all new O-rings on the system pressure regulator check valve.  Did
>this 2X because I had gotten the inner and outer mixed up the first time,
>ruining the outer.
> >
> > Now I get about 85%system pressure(was 90 PSI) on both sides(same with
>the correct o-ring placement as with the previous botched job), so I
>attribute this to something I did wrong, but can't figure what exactly.
>  The outer O-ring is a sloppy fit and tends to slip out of the seat on the
>shaft when inserted.  Anyway, now  I am sure the correct o-rings in the
>right spot, but it is screwed up worse than before I touched the check
>valve.
> >
> > Maybe the system is totally blocked now at the c.p. regulator. Pump on
>->
>system pressure.  When the pump is off,  pressure still equal on both sides
>and drops to about 50 PSI.
> >
> > I am going to check the screens on the c.p. regulator this afternoon.
>  How much insanity is disassembling and cleaning it.
> >
> > Probst also suggests a blocked return line.  where might it get blocked?
> >
> > What else should I be looking at?
> >
> > Thanks for the support!
> >
> > Ben
> >
> > On Tuesday, April 16, 2002 6:02 AM, Graham Thackrah
>[SMTP:gthack at geog.ucl.ac.uk] wrote:
> > > Hello Ben,
> > >
> > > Sorry if this is a bit late, I took a look through Probst's FI book
>and
>it
> > > shows a plot in there with system pressure rapidly falling to c. 3 bar
> > > after shutdown, which it is supposed to hold for a few hours, but then
>SP
> > > drops off to zero after a prolonged period of time "through various
>minor
> > > leaks in the fuel system." I'm not sure if total leakdown overnight is
> > > undefined behaviour for CIS systems. One place it did say to check on
>CIS
> > > systems suffering fast leakdown is the system pressure regulator, it
>has 2
> > > O rings in it and you can buy a kit from the dealer with new ones in.
> >
> > Right I just got 2 kits today.  Used/abused the one I had last week.  Of
>course the Bently blowup does not show detail, and the kit has no
>instructions.  Almost lost that tiny c-clip that retains the shaft which
>has the outer(control pressure?).
> >
> > > Dodgy O rings in there could cause both control and system pressure
> > > leakdown, one O ring seals off the return from the CPR and the other
> > > system pressure return to the tank.
> > >
> > > hth,
> > >
> > > Cheerio,
> > >
> > > Graham.
> > >
> > > P.S. just in case - and sorry if this is teaching you to suck eggs! -
>but
> > > when testing cold control pressure you did disconnect the CPR heater
> > > didn't you?
> >
> > Yes
> >
> >  I got that wrong a few times when I was checking my own car
> > > out but I think if you jumper the FP relay it also sends a feed to the
>CPR
> > > heater so you'll be testing warm CPR operation even though the engine
>is
> > > not running.
> >
> >
>
>


_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.