Difficult starting after 1 week parked up

mannyo · #1 27th July 2012, 07:40 PM

I have been driving another car all week, so this evening went to go out in the A8. This is first time its been started for 8 days, and I almost got to the point of getting out and using the other car I am currently driving.

Basically, I got in and it turned over fine started and run for about 1 second before spluttering to a halt. Tried again, and it was turning over but not catching. I had to resort to planting my foot on the throttle, and operating the starter. Eventually after 20 seconds it started to catch, and after 30 seconds it finally decided to run albeit very lumpy. There was a nice smell of unburnt fuel from the exhaust. The CEL came on, and after idling for a couple of mins all was normal again. After a short drive all is fine again, it starts fine and drives fine.

The A8 is getting another couple of weeks off, so if it was like this after 1 week, I wonder how bad it will be after two.

ainarssems · #2 27th July 2012, 08:07 PM

Possibly small leak in fuel system let the air in while it was standing.

Conan_the_Librarian · #3 28th July 2012, 08:31 AM

^^^^ What he said. Check the fuel filter Also remember that thefuel pump is a technical marvel and actually dosen't pump fuel from the tank to the fuel rai rail; it pumps fuel from the tank to a seperate chamber in the fuel pump assembly and thence to the fuel rail. If this chamber drys out the pump has the devils own job to refill itself as it uses some of the fuel to drive the turbine pumps in the tanks that send the fuel to the chamber!!!!!!! Try pouring 5 lts into the tank from a can before starting as this floods the chamber before running into the bottom of the tank.

Audi desined it this way to overcome the 2 low poins in the tank either side of the prop shaft. It keeps the weight distribution equal in unequal volumes of the tank low points.

mannyo · #4 28th July 2012, 07:09 PM

The car has been fine today, used it several times and started perfectly as normal. Tomorrow I'll be leaving it where I am now in Hertfordshire for 2 weeks whilst at home in Dorset, I am then off work for a week and will try and get some minor issues sorted with the 8 whilst I am on holiday back here in Hertfordshire. The 8 is not usually left for more than a couple of days, the current situation is quiet unique.

Architex_mA8tey · #5 28th July 2012, 07:55 PM

I would take a can with a few litres and pour it in just prior to starting as CtL has suggested and that will hopefully prevent the same happening again when you get back

ainarssems · #6 29th July 2012, 09:44 AM

There is no reason why fuel would escape baffle housing while car is standing for a while unless it's cracked in which case it would not take week but it would leak out much more quickly. And would only affect if there is less then 1/3 of tank.

I don't think messing with can is the way to do it. When you switch on ignition fuel pump runs for 2-3 sec to prime the system. Just cycle ignition 5-6 times for 3-5 secs each time to get some fuel in system before starting. You would do the same after work done on fuel system like changing filter or fuel pump etc.