Audi A3 TDI Does not start when fuel less than half a tank

**keenu** · 06-08-2013,11:46 AM

I purchased an Audi A3 TDI 2006 (BKD engine) around 4 months ago and it developed a fault whereby if the fuel level was below half a tank it would not start. This only happens when the car has been left overnight. It cranks fine but it seems it’s not getting any fuel. It can be started with easy start or when the fuel level is raised again to above half a tank.

I took it to the Audi dealer and they first diagnosed fuel contamination (oil leaking in fuel perhaps?). Tank was emptied, new fuel filter and fuel lines cleared. Got the car back and same thing happened.
Again I took it to the dealer and they then replaced the in tank fuel pump. Again the same problem occurred with the same symptoms. There are no fault codes or anything and I believe the dealer hasn’t got a clue what’s wrong.

Any ideas what it could be? I think it’s definitely a fuel issue but what to try next? Could it be a tandem pump issue? I have read these are prone to failures. I have already spent over £900 on this and still no fix so I want to make sure the next thing I do does fix the issue.

Thanks for your help.

**zollaf** · 06-08-2013,11:48 AM

welcome

right, when the tank says its half full, how much fuel is in the tank ? is it actually half full or is it empty.

**keenu** · 06-08-2013,11:54 AM

Originally Posted by zollaf

welcome

right, when the tank says its half full, how much fuel is in the tank ? is it actually half full or is it empty.

Hi, Its just under half a tank, not empty at all.

**zollaf** · 06-08-2013,12:32 PM

definately, this has been checked by removing the pick up and physically looking or just brimming the tank and seeing how much fits ?

**Alan02** · 06-08-2013,04:27 PM

HI, I would be looking at the oil in the fuel problem, as you mention you have had the tank pump replaced, you should be getting an accurate reading.
The oil in the tank will be causi g some seperation and possibly cause your bad starting.

**keenu** · 07-08-2013,09:17 AM

Originally Posted by Alan02

HI, I would be looking at the oil in the fuel problem, as you mention you have had the tank pump replaced, you should be getting an accurate reading.
The oil in the tank will be causi g some seperation and possibly cause your bad starting.

Thanks, do you think a leak in the tandem pump can cause oil to mix in with fuel? How else can oil get into the fuel tank?