Audi 100 Won't Start: Removal of Injector

[Marc Boucher]

I've performed the test below.  Fuel line to an injector removed and engine
cranked.  Once with the boot on (I've previously confirmed that the plate is
lifting during cranking via measuring potentiometer).  A second time for
further certainty with the boot removed and holding the plate wide open.
Both cases NOTHING.  No fuel is being sent out of the top of the distributor
to the injectors (with exception of the cold start which we know is
working).  For further certainty I pulled a second injector with same
result.  I could see a bit of gasoline down the hole but it wasn't going
anywhere.

Note that for safety reasons I'd removed the central wire from the
distributor and grounded it as per the Hayes manual.  I performed this test
with trepidation and with a fire extinguisher, pin removed and ready at my
side.

If I understand correctly, not only should gas have shot out while cranking
the engine, it should even have shot out from when the bolts were pulled
since (when working as designed) the injectors are kept pressurized.

Nothing more to do.  But since it looked simple to remove I undid the two
bolts holding the differential pressure regulator.  Gasoline shot out under
pressure (a small amount).  The regulator looked clean and clear and was not
plugged in any way.

So I guess this points to the metering device?  Anything to do but buy a new
one?  Should I spay inside the metering device with Carb Cleaner or WD40 or
contact cleaner?

If I do need a new metering device, anyone have a part number or suggestions
on how/where to get one at a decent price ?

Also what exactly is the tool that I need to remove the fuel distributor?
An allen key will work but its really a star shaped (8 points?) and not a 6
sided allen key.

Thanks

Marc


----- Original Message ----- 
From: "Doug Yoder" <yoderw at msoe.edu>
To: "Marc Boucher" <mboucher70 at hotmail.com>
Cc: "Kurt W. Deschler" <desch at WPI.EDU>
Sent: Friday, January 30, 2004 10:03 AM
Subject: Re: Audi 100 Won't Start: Removal of Injector


Marc-

I have 2 cars with NF engines... '91 100 and '87 5ks.  On the 100, the
IM curves around half over the top of the valve cover [1].  On the 5ks,
the IM doesn't curve around as far, and there is enough room to get at
the injectors.  It is very helpful to have a injector puller [2], they
cost about $8 from your imports parts place.
If you don't want to mess around with pulling the injectors, use a 12mm
wrench to losen or remove the fuel line from the top of the distributor.
  Remove the air boot, pull up on the air flow plate, and have an
assistance turn the key *briefly*.  You should see a jet of fuel coming
out the top of the distributor.  If you do, there is either something
horribly wrong with the injectors, or not enough pressure in the
injector lines to open the injectors.

Good luck,
-Doug

[1] IIRC, this is known as a NG-style NF.  The NG and NF engines are
almost identical except for IM style.  But there are a few NF code
engines with NG style heads.  Audi just wanted to toy with us that year
I guess.
[2] Like this:
http://toolcraze.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=T&Product_Code=S8CFIP&Category_Code=spec