2005 A6 losing power

[Red-penquin]

Hi, am driving a 2005 A6 2.0 tdi. Was having probs @ 2500 revs, stuttering etc, so got new fuel filter on Fri which did the trick. Was away at weekend and on 3 seperate occasions car semmed to 'lose power'. Sitting maybe at 65mph, tried to accelerate, foot to the floor, revs went up but no acceleration? Dropped down gear, speed to 50mph, same thing but very slowly crept up, and i mean VERY slowly! Stopped car, left it off for a couple of mins, started, and back to normal. A while later, same thing when hitting about 70mph, so turned car off, couple of mins, and back to normal again! Anyone have any ideas please???

[paul b]

Possibly a blocked catalytic converter?

[Red-penquin]

Possibly a blocked catalytic converter?


Cheers Paul, big job?

[Teflon]

Hi, am driving a 2005 A6 2.0 tdi. Was having probs @ 2500 revs, stuttering etc, so got new fuel filter on Fri which did the trick. Was away at weekend and on 3 seperate occasions car semmed to 'lose power'. Sitting maybe at 65mph, tried to accelerate, foot to the floor, revs went up but no acceleration? Dropped down gear, speed to 50mph, same thing but very slowly crept up, and i mean VERY slowly! Stopped car, left it off for a couple of mins, started, and back to normal. A while later, same thing when hitting about 70mph, so turned car off, couple of mins, and back to normal again! Anyone have any ideas please???
This seems to be a really common set of symptoms for 1.9, 2.0 and 2.5 TDI's and there are numerous threads on here for you to take a look at. I'm a fellow sufferer and am only just getting to the bottom of it. In approximate order of increasing cost, the causes seem to be:

air leaks on vacuum hoses around the turbo
MAF sensor - clean it
Fuel filter - change it
MAF sensor - change it
MAP sensor
N75 valve
boost pressure/crankcase relief valve
turbo sooted up, causes underboosting or overboosting and drops into limp mode.
cat converter blocked up
turbo stufffed - need a new 'un.

Before you dive into changing anything blind, it's a good idea to find a garage with a diagnostic computer and get the fault codes read and diagnosed. I've had all the ones in blue diagnosed (and sorted out). If the problem starts to get progrssively worse and more frequent, that seems to be a good sign that the turbo needs cleaning.

I hope this helps and that the solution is easier to find than mine was!

[Red-penquin]

This seems to be a really common set of symptoms for 1.9, 2.0 and 2.5 TDI's and there are numerous threads on here for you to take a look at. I'm a fellow sufferer and am only just getting to the bottom of it. In approximate order of increasing cost, the causes seem to be:

air leaks on vacuum hoses around the turbo
MAF sensor - clean it
Fuel filter - change it
MAF sensor - change it
MAP sensor
N75 valve
boost pressure/crankcase relief valve
turbo sooted up, causes underboosting or overboosting and drops into limp mode.
cat converter blocked up
turbo stufffed - need a new 'un.

Before you dive into changing anything blind, it's a good idea to find a garage with a diagnostic computer and get the fault codes read and diagnosed. I've had all the ones in blue diagnosed (and sorted out). If the problem starts to get progrssively worse and more frequent, that seems to be a good sign that the turbo needs cleaning.

I hope this helps and that the solution is easier to find than mine was!


Thanks for such a comprehensive answer, much appreciated! Well, it seems the solution was easier to find. I brought my 2005 A6 to my own mechanic (avoided the ********) and he put it on the diagnostic computer which found a fault in the fuel filter cap/screw which was causing a leakage and loss of pressure thus causing the loss of power. New cap on filter, good as new, and better than that, no charge..... what a result :D Thanks for your help on this one :beerchug:

[paul b]

Don't you love happy endings. LOL :biglaugh:

[Red-penquin]

Don't you love happy endings. LOL :biglaugh:


Oh yes......... :fest30:....... but not getting too carried away, cars are crafty buggers... :(

[paul b]

Oh yes......... :fest30:....... but not getting too carried away, cars are crafty buggers... :(
LOL... ;)

[Mike McKinstry]

Hi ,
I have similar intermittent fault but now you mention it this symtom started to occur shortly after a fuel filter change.Can you clarify what exactly was wrong with the filter and what was don eto resolve it please.
Many thanks,
Mike.

[Red-penquin]

Hi, apparently the 'key' at the fuel filter was faulty, there's 2 little rings on the thread which seal it, and one of these was faulty. The 'key' i'm talking about is black plastic, and shape and size would remind you of a 'bleeder' for a radiator (home heating type, not car radiator) Hope this helps in some way.

[Mike McKinstry]

Thanks mate.
I am going to assume your filter is same as passat and that it is the seals on the allen key headed bolt you are referring to.Maybe it is worth getting another filter with correct seals and relacing -was going to go down MAF/turbo route as suggested above!

[Red-penquin]

Thanks mate.
I am going to assume your filter is same as passat and that it is the seals on the allen key headed bolt you are referring to.Maybe it is worth getting another filter with correct seals and relacing -was going to go down MAF/turbo route as suggested above!


Thats exactly what it is, i knew it looked like something other than a radiator bleeder, allen key..... :Blush2: Good luck, hope ur as lucky as I was :beerchug:

[Mike McKinstry]

Cheers-I hope so.


Regards.