quattro digest, Vol 1 #5288 - Long Starts

[Larry C. Leung]

I'd have to concur with the others, your injectors are likely leaking
down.
Why running the pump doesn't just fill the injectors is, the pump won't
start
until the coil fires, which won't happen until the engine starts to spin
up. (fuel safety
cut-off) So, the injectors leak, draining the lines, (possibly thining
the oil with time),
and until the coil starts to fire, there's no fuel pressure in the lines,
thus cranking until
the lines fill. Usually takes awhile to get them to leak out, not sure if
your temp
relationship is truely correlated, generally happens when the car sits
for awhile
(hot or cold out) and the fuel leaks out. BTW, totally do-able without
the removal
of too much stuff, injector cooling shroud (heed ALL cautions, when it's
this old,
it may crumble and it helps the hot starts by reducing/eliminating vapor
lock), PERHAPS
you may to release a line from the fuel distributor (keep things CLEAN
and have
new crush washers handy) to gain access, but that's not a given. Just be
sure that there
is little to no pressure in the lines before breaking into things
(disconnect coil and
crank until there is no start tendencies). Also helps to have an injector
puller, there
are many listings in the archives on ones people have made if you can't
find one.
Takes about 1 hr if your being slow, careful and doing it the first time.
(BTW hardened
seals as likely with your car's age will take some effort in pulling. The
new Viton (green)
sealed injectors will just simply pop right in).


HTH,

LL - NY

BTW, before you go replacing the knock sensor (the code thrown) fix the
injectors,
clear codes, and then see if it throws the code again. May save you a few
$$ if the
sensor is okay after the injector job.



> To: mulieri at physiology.med.uvm.edu
> Cc: quattro at audifans.com
> Date: Mon, 18 Aug 2003 11:40:48 -0400
> Subject: Re: Long Starts
> From: cobram at juno.com
>
> This is a common problem on the Turbos when the mileage and the age
> get
> up there.  Change the Fuel Injectors and your problems should be
> solved.
>
> They're not that hard to change, plenty in the archives and the
> Bentley
> covers
> the fuel system in detail.  Just be careful with the injector
> cooling
> shroud (if so
> equipped), they get brittle with age.
>
> Get a copy of the Probst book on Fuel Injection or check out:
> http://www.students.tut.fi/~hezekiel/bosch.htm
> to get a feel for the system, should address technical questions.
> Lots of other links if you check the root URL.
>
> You can pre-pressurise the lines, but it'll have to be done by
> bringing
> up
> the throttle plate manually while jumping the fuel pump relay.
>
> BCNU,
> http://www.geocities.com/cobramsri/
>
> "Louis A. Mulieri" <mulieri at physiology.med.uvm.edu> writes:
>
> > there a way to confirm your diagnosis without taking the
> injectors
> > out?
> > I'm really trying to avoid taking the injectors out because it
> > looks to me like I'd have to take off the intake manifold to get
> at
> > them because of the turbo clutter. Am I missing something here?
> >         What do you think about testing the empty injector line
> > theory by
> > opening one or two at the fuel distributor end to look for fuel
> > before a cold morning start and again before a hot morning start?
> >         Can you explain why the lines don't fill by just keeping
> the
> > key in ON position for a while before cranking?
>
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