RE: Easy Staring with Fuel Pump Prep Run

["Robert Dalton" <rpdalton@onebox.com>]

Thanks!  I think this 3 second fuel pressure prep
is supposed to happen every time.  It's probably
a simple timer type function that happens each
time the ignition switch is turned on (to run).
 My gues is it's controlled by the ignition control
unit.  The ICU probably doesn't monitor fuel pressure
at all, but uses the dumber approach of simply
turning the fuel pump on for 3 seconds each time
the ignition is turned on.

I think my ignition switch is actually going intermittant,
because there are deffinitely times when this 3
second prep doesn't occur.  Usually this is most
likely to happen after a long overnight sit, when
it is needed most to build up fuel pressure.  Without
that 3 second prep, the car cranks a long time
before starting.

I just noticed that turning the ignition off (without
trying to start it) and back on again so far has
always resulted in the pump coming on for its 3
second prep run.  This sounds like the ignition
switch to me.  Interestingly, the maintenance records
of the former owner show replacement of check valves,
wires, rotor, coil and other items at an attempt
to fix hard starting.  Wouldn't it be something
if years later, the problem really turns out to
be an intermittant ignition switch.      

I don't think my 1990 Audi 100 (or any 89 to 91s)
have the computer monitor fuel pressure, since
that's the self contained job of the regulator.
 

-- 
Robert Dalton
rpdalton@onebox.com - email
(703) 234-3969 x1020 - voicemail/fax



---- "Iain Atkinson (ETL)" <iain.atkinson@etl.ericsson.se>
wrote:
> My wifes 100 does this also, I just put it down
> to the fuel system coming up to pressure, although
> I think if I were to switch it off again and
> then on it would do the 3 second thing again.
> 
> Iain
> 
> -----Original Message-----
> From:	Andrew Duane USG [mailto:duane@hunch.zk3.dec.com]
> Sent:	20 December 1999 12:48
> To:	rpdalton@onebox.com
> Cc:	quattro@audifans.com
> Subject:	Re: Easy Staring with Fuel Pump
> Prep Run
> 
> Hairy green toads from Mars made Robert Dalton
> say:
> 
> > Could I have a check on this?  Those of you
> with
> > 1989 t0 1991 Audis, can you hear your fuel
> pump
> > run for about 3 seconds when the ignition switch
> > is turned on (to run)?
> 
> My '89 100Q did this, and my '90 90Q20V does.
> 
> Haven't noticed whether the A6QW does....
> 
> -- 
> 
> Andrew L. Duane (JOT-7)			duane@zk3.dec.com
> Compaq Computer Corporation		(603)-884-1294
> 110 Spit Brook Road
> M/S ZKO3-3/U14
> Nashua, NH    03062-2698
> 
> Only my cat shares my opinions, and she's too
> psychotic to express it
> 
> 

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