RE: Audi 5000 Fuel Distributor

[Dave Shreeve <shreevda@cannondale.com>]

Thanks for the advice.  I agree.

Now some more background info...  At the time, I was 400 miles from
home, without time, without tools, with wife and two small children, and
with a vehicle that would barely run from a stop.  Had to drive it
anyway - had little choice at that juncture.  (Fully intended to explore
all relevant components in detail once I got home - I figured I was in
for a new injector or fuel distributor, and soon.)  Whew.  ;-)

I wasn't TOO worried about high EGT, as problem disappeared at cruising
speeds.  Only seemed to affect initial acceleration/spray onset from
injector.

To reiterate Steve - anyone with similar symptoms should check things
out as soon as possible.  Especially if you don't, and they persist.

-David

> ----------
> From:
> steveb@falcon.kla-tencor.com[SMTP:steveb@falcon.kla-tencor.com]
> Sent: 	Wednesday, December 3, 1997 3:21 PM
> To: 	quattro@coimbra.ans.net
> Subject: 	RE: Audi 5000 Fuel Distributor
> 
>  # I developed the exact same symptoms last week with my '88 5kcsqw.
>  # Figuring it was either the fuel distributor valve or a fouled
> injector,
>  # I ran two tanks with injector cleaner added to see if I might get
> lucky
>  # and avoid replacement of the offending part.  After about 200
> miles, the
>  # problem had diminished to nothing.  This chilly morning, a few days
>  # later, a slight miss returned - but disappeared again as the car
> warmed
>  # up.
>  # 
>  # I suspect I've got an injector that was sticking in the closed
> position.
>  # I am leaning toward this as an explanation, because the engine felt
> more
>  # like there was a distinct cylinder miss than a more general lean
> state
>  # from a sticky distributor valve.  We'll see how it does after a few
>  # months...  maybe a good cleaning will manage the problem.
> 
> ... you really need to be careful not to be "penny wise and pound
> foolish" 
> when you do things like this.  If you have a cylinder that is running
> lean 
> due to a malfunction of the FD or injector your EGT can get much
> higher 
> than nominal.  This may result in burned valves if it goes on for too
> long.  
> I suppose that if the injector were completely plugged you wouldn't
> have a 
> problem as you'd simply be pumping air ...
> 
> I'd recommend that anyone that thinks they have an injector problem
> pull 
> the injectors and check the spray patterns rather than running a
> bottle 
> of Techron and crossing your fingers.  It really isn't that difficult
> to 
> pull the injectors out to check them ... and that would also give you
> a 
> chance to see what shape the seals are in ...
> 
> ... to the original poster ... if you have a problem that develops as
> the 
> engine warms up it may in fact be due to the ECU trying to lean out
> the 
> mixture when it goes closed loop.  Too bad the car doesn't have an EGR
> 
> valve ... the symptoms fit pretty closely to that.  :)  Here I'd
> recommend 
> that you get a fuel pressure gauge and a duty cycle meter and check
> system 
> and control pressure as well as the "OXS duty cycle."  Another
> possibility 
> you might want to look for is an intermittent vacuum leak ... and the
> can-
> didate I'm thinking about is that stupid hose that runs up the spark
> plug 
> side of the engine and connects the crankcase to the "PCV" system.  I
> cur-
> rently have that silly thing covered with duct tape on the '88 5kCSQW
> ...
> 
> HTH!
> Steve Buchholz
> San Jose, CA (USA)
>