[urq] Warning about Fuel Pressure Accum.

[Ben Swann]

Note - not in all cases will simply turning the key on enable the fuel pump
relay.  To really do this one must jumper the relay contacts.  30 - 87
AFAIR - the larger contacts which can be bridged with a wire  at least 14
Guage with spade lugs on both ends.

I agree that if charging the system up by running fuel pump and then engine
starts promptly, then there is a likely leakdown system pressure side of the
fuel distributor.  Essentially from the fuel pump to the plunger portion of
the fuel distributor - oversimplification of course..and don't forget about
the control pressure regulator - not the warmup regulator, which can also be
a problem.

Ben
----- Original Message ----- 
From: "Patrick Carlier" <p.carlier at pandora.be>
To: "SpotatAshleys" <spotatashleys at hotmail.com>; "Ben Swann"
<benswann at comcast.net>
Cc: <urq at audifans.com>; <quattroguy83 at yahoo.com>; <quattro at audifans.com>
Sent: Wednesday, January 28, 2004 4:20 PM
Subject: Re: [urq] Warning about Fuel Pressure Accum.


> Keith , have you tried this :
>
> Turn on the ign key , but don't crank .
> You should be able to hear the the fuel pump running for a few seconds .
> Repeat this several times in a row : allow the pump to run till it
switches
> of ,
> switch off the ign and turn the pump back on .
> This will allow you to build up pressure on the fuel system .
>
> If after that the car starts normal or much better , you have either a
> leaking check valve
> or a broken accumulator .
>
> Pat
>
>
> ----- Original Message -----
> From: "SpotatAshleys" <spotatashleys at hotmail.com>
> To: "Ben Swann" <benswann at comcast.net>
> Cc: <urq at audifans.com>; <quattroguy83 at yahoo.com>; <quattro at audifans.com>
> Sent: Wednesday, January 28, 2004 8:59 PM
> Subject: Re: [urq] Warning about Fuel Pressure Accum.
>
>
> > Thanks Ben (and others too)
> > In an effort to cure the long cranking I replaced all the injectors
first
> > but still have the problem hence my questions now about the accumulator.
> The
> > battery is brand new and very good. It always starts (so far) but after
an
> > inordinate time cranking.
> > It looks like keep replacing things till it starts properly and the
> > accumulator could be next unless someone has a bright idea.
> > Thanks again
> >
> > Keith
> >
> > '87 WR
> > ----- Original Message -----
> > From: "Ben Swann" <benswann at comcast.net>
> > To: <ashleyj.cobain at virgin.net>
> > Cc: <urq at audifans.com>; <quattroguy83 at yahoo.com>; <quattro at audifans.com>
> > Sent: Wednesday, January 28, 2004 5:27 PM
> > Subject: [urq] Warning about Fuel Pressure Accum.
> >
> >
> > As you mention, when operating correctly, the accumulator should help
> > maintain the fuel pressure to around 35 PSI after shutoff if there are
no
> > leaks in the system.
> >
> > The FP accumulator also act as a damper to smooth out pulses/spikes in
the
> > pressure.  Analogous to the vertical tube a plumber would install to
> prevent
> > water hammer when a faucett is closed rapidly in a plumbing system, but
> also
> > similar to the water pressure accumulator used on well fed systems - a
> tank
> > that holds water with a bladder full of air at the top.  The accumulator
> on
> > the fuel injection system uses a spring instead of air to maintain this
> > pressure.
> >
> > As you allude to a faulty pressure accumulator can cause hard starting,
> long
> > cranking.  I have found more often, a leakdown on the injector side of
the
> > system is the problem, and the accumulator is secondary.
> >
> > Ben
> >
> > [Please excuse my ignorance but what is the precise function of the fuel
> > accumulator?
> > It is supposed to maintain system pressure when the engine switched off?
> In
> > other words could this be my problem with cold starts? Hot starts are
> fine.
> > Mixture is not a problem during cold starts, once started. The warm up
> > regulator is working because the air fuel meter shows it is doing it's
> job.
> > The problem is that I have to crank it lots before it fires. Is this
> because
> > it has lost system pressure over night and I then have to crank for fuel
> > pump to restore pressure?
> >
> > Look forward to receiving your thoughts
> >
> > Keith
> >
> > '87 WR]
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