[s-cars] Fuel Rail Leak

[Varon H. Fugman]

I too had the leak where the fuel supply line connects at the firewall.  I
just replaced my fuel rail last Saturday, so I'll throw in my $0.02 as
well...

1. It appears that the fuel rail and fuel supply line are separate parts
with a banjo bolt at the front end of the fuel rail (as shown in Bently) on
the '92-'94 S4, but on the '95-'97 S6 it is a single one-piece assembly.

2. Mine leaked two years ago in December on an 8 degree F day.  There was a
steady drip drip drip of fuel from the connection.  Wish I had thought to
document it with the camcorder!  I had smelled gas under the hood the
previous April on two occasions, but never localized it, only determined it
wasn't from the turbo side of the engine.

3. Replacement fuel rail assembly took 12 weeks to arrive from Germany.  I
suspect some German craftsman somewhere has to assemble all the parts on a
jig and braze the whole thing together.

4. After a week, I experimentally drove the car again.  No leak.  Ended up
putting the car back into service.  No more leak again.  For two years,
including cold temperatures.

5. The fitting where I had the leak swivels where the rubber hose is crimped
onto the metal fitting (the part with female threads.)  Sounds like Mark's.
I don't think this crimped connection is supposed to swivel.  None of the
other similar crimped connections swivel.  The crimped connection on my new
fuel rail assembly does not swivel.

6. All the connections on the *new* fuel rail assembly are double-crimped.
They look similar to the double-crimped connections by the fuel filter on
the piece that was replaced under the recall.  I suspect they became aware
of problems with the single crimped connections and went to the double crimp
as a solution.

7. If I had known the new $300+ fuel rail was going to take 3 months to
arrive (I was told 1 week), I would have taken the old one to a shop that
makes up hydraulic hoses to see what they could do (i.e. maybe crimp on a
new end.)  However, I would not try any home-brew solutions involving
clamps... this is a high-pressure fuel system!

8. I shouldn't have waited two years to replace my fuel rail, but since it
wasn't leaking any more the immediate motivation was gone.  Took another
leak back at the tank to force me into working on the fuel system.
Replacing the fuel rail assembly itself is a pretty easy job.

9. Bill, having the recall done recently could have caused, or at least
precipitated the leak if the tech wasn't careful to hold that side still
while turning the part with the male threads on the fuel supply line at the
firewall.  In other words, there is a good chance that while
disconnecting/reconnecting the line some swiveling action happened at the
crimp, leading to the leak.  My leak happened 3 months after some major
engine work.  If it hadn't been for the fuel smell earlier, I would have
blamed this for my leak.

10. I am thinking of writing to AoA to see if they will reimburse me for my
fuel rail (and sender assembly, but that is a different fuel leak!)  Not
sure if it is worth my time to follow up with them or not.  Any thoughts?

11. I am wondering if I should file a report with NHTSA on my two fuel
leaks.  I don't want to punish Audi (and thus discourage them from bringing
special cars to the US), but I don't want anyone to get burned (either
figuratively or literally.)  Too bad AoA isn't being more proactive about
this.  I know of at least 4 types of fuel leaks on these cars: [a.] near
turbo, line replaced by recall, [b.] fuel rail supply line leak at firewall,
[c.] fuel line under the car at the rubber bushings, and [d.] fuel sender
assembly at the top of the tank.

OK, that ended up being more like $0.11 worth.  Sorry so much, just wanted
to make sure I am sharing anything that will help anyone!

Varon
'95 urS6 w/new fuel rail, filter, and sender assembly