Crashbot71

After the cold weather last few weeks my 01 A8L had an "EVAP Small Leak" error which cleared after refueling but, a day later when the temp was below 0 I started to smell gas fumes, then the car would start rough and then run normal. Now I have to turn the ignition twice to start it. I hear the fuel pump when first starting so I eliminated that. If anyone can offer some advice as to what to look for diagnosing this, it would be helpfull. Thanks.

twentysevenlitres

'Small Evap Leak' tends to point to something in the tank as the system runs a leak test at start up I believe.
Common issue with D2's is the o-ring seal under the fuel level sensor cap on top of the fuel pump housing. During cold weather these often leak - especially when the tank is full - giving a petrol smell in the car.
If it goes away after 50 miles or so, I'd put money on it being your culprit.
You can buy a kit for it from the dealer (new cap and seal - 4D0298135B).
It used to be $5, but for some reason is now over $40. You can try the Audi Tradition shop at audi.de, they sell it for around 5 Euros plus freight I think.

The other common failure is the high pressure fuel hose fitting at the fuel rail on the engine. Pull the top engine cover off and you should be able to see it on the (LHD) passenger side towards the back of the inlet manifold.

Beyond those two, you may need help.

S8ilver

I'm chasing a P0442 "small evap leak." It could be any number of things beyond the tank o-ring or a fuel hose fitting. I have no gas smell, so I started with vacuum lines. Many crumbled in my hands after I pulled them off, so that was a good place to start regardless (and they're cheap and easy to do). My code stayed. Next I replaced the evap purge valve and the code went away for a couple months or so. The code is now back. Ok, maybe it's the gas cap. I cleaned it thouroughly and still no dice. I replaced that and the code won't leave. Next I plan looking at the evap canister itself and the leak detection pump. Hopefully repairable as now I'm getting to the more expensive items.

Vacuum lines (silicon) - $25
Purge valve - $45
Gas cap - $13
Evap canister - $250ish
LDP - $450ish

Beyond those I'm lost as well. Anyone else have this code?

S8ilver

So this is odd. I don't know what I did, but the "small evap leak" code P0442 is gone.

I pulled the evap canister to inspect. No fuel in it and the three hoses all looked good. I replaced with the standard worm gear hose clamps and bolted it back under the car. While I had the rear tires on ramps I decided the fuel filter could use a change. Ok, easy job.

I cleared the CEL and took a drive. It usually takes about 30 miles and/or a couple restarts to trigger the code. I was waiting and waiting for it to come back, but a weekend of driving and 70 miles later, the code appears to be gone for good.

Could the fuel filter have anything to do with the fault? The original crimp-on hose clamps at the evap canister seemed to be on there tight as the day they left the factory. I'm simply stumped as to what fixed the leak.