3.0 TDI problem

**a8 tech** · 01-10-2009,07:36 PM

never noticed Toff but suspect intake manifold change over returning to its open position

**adamss24** · 01-10-2009,08:52 PM

Originally Posted by a8 tech

never noticed Toff but suspect intake manifold change over returning to its open position

Thats the one, does it in any v6 tdi engine i've worked on...

**KQuattro** · 02-10-2009,09:23 PM

Fault codes guys...will be changing fuel filter. Can faulty fuel filter throw up all these faults ?

**a8 tech** · 02-10-2009,09:25 PM

Yes checking the rail pressure switch can also help by simply disconnecting the sensor on the right bank rail the fuel pressure defaults and performance will return if the sensor is faulty.
The high pressure pump driven by the aux belt can fail internally causing swarf to circulate around the fuel system.

When the filter blocks the fuel supply from the pressure pump the high pressure sensor reads a drop so the required rail pressure cant be reached for injection.

The filter issue affected B7 and 4F A6 2.7 and 3.0 common rail and the manufacturer of the filters has since been replaced although no recall was issued only a few vehicles were affected but I replaced a filter for this very issue on Monday

**KQuattro** · 03-10-2009,09:49 AM

Originally Posted by a8 tech

Yes checking the rail pressure switch can also help by simply disconnecting the sensor on the right bank rail the fuel pressure defaults and performance will return if the sensor is faulty.
The high pressure pump driven by the aux belt can fail internally causing swarf to circulate around the fuel system.

When the filter blocks the fuel supply from the pressure pump the high pressure sensor reads a drop so the required rail pressure cant be reached for injection.

The filter issue affected B7 and 4F A6 2.7 and 3.0 common rail and the manufacturer of the filters has since been replaced although no recall was issued only a few vehicles were affected but I replaced a filter for this very issue on Monday

Thanks A8_tech getting filter changed today and see how it goes....this is the only problem I have had. I did change the fuel filter 15k miles ago as part of the service at 40k miles as indicated in the service book, could be that I got a bad one.

Cheers Ray

**KQuattro** · 05-10-2009,02:45 PM

Changed fuel filter, same problem. Will look at the sensor next.

Why would the high pressure pump fail ? i dont think this is a common fault ? are they prone to failure ? I hope its not that as that will be very expensive...surley the pump should not fail at 55k miles ?

One of the reasons it would fail is if someone put petrol in instead of diesel due to lubrication.

**mudzs** · 05-10-2009,03:31 PM

my car kept cutting out for no reason and would not start , then it would start when left but only drive for a while before cutting out again with the coil light flashing , turned out to be the main fuel pump , audi changed the one in the tank first as this was the cheaper option to start with ... all fine now but a very exspensive part to buy and fit .

**a8 tech** · 05-10-2009,08:10 PM

Originally Posted by KQuattro

Changed fuel filter, same problem. Will look at the sensor next.

Why would the high pressure pump fail ? i dont think this is a common fault ? are they prone to failure ? I hope its not that as that will be very expensive...surley the pump should not fail at 55k miles ?

One of the reasons it would fail is if someone put petrol in instead of diesel due to lubrication.

Ray i would suggest either the fuel delivery is poor from the pressure pump in the tank or the high pressure sender.The high pressure pump is possible but if there's insufficient pressure before the pump then high pressure pump will not produce the correct pressure required hence the fault code.

**KQuattro** · 05-10-2009,11:10 PM

Originally Posted by a8 tech

Ray i would suggest either the fuel delivery is poor from the pressure pump in the tank or the high pressure sender.The high pressure pump is possible but if there's insufficient pressure before the pump then high pressure pump will not produce the correct pressure required hence the fault code.

Fingers crossed then...going to book it in with Audi and see whats what.

**mudzs** · 06-10-2009,03:26 PM

Mine was in audi for 3 weeks trying to sort this problem , they said they could see bubbles in the fuel line so changed to pump in the tank. however when i picked up car it cut out again within 10 miles , so they changed the high pressure pump . been a very unreliable car and the last audi i will ever own