A3 TDI - no power!

[nickd01]

My partners A3 (Y-reg) 1.9 TDI has zero power, it literally feels like some one has taken the turbo!

Around 2k revs there is a slight surge but after that it simply gets nosier and no faster! On the motorway with an incline it noticably slows; sometimes to 50/60 on a long incline.

I can hear (I think) the turbo whistling on acceleration but I swear it's not doing anything.

Is there anything I can do to see whether the turbo is knackered? It's not smoking or chewing oil.

Nick

[Tame Technician]

Try the car with the air mas disconnected, if its better, you need a new one.

But you need the codes read really. As there are a number of engine management faults that could cause that. Just remember to ignore one for Air mas open circuit if you ran the engine with it unplugged.

If there are no fault codes, it either needs an air mass meter or a boost pressure sensor. These can fail but not show up in the fault memory. In these cases, You really need to monitor the boost pressure while your driving. But it sounds like that might be OK if you can here the turbo spinning, which would suggest air mas, but they tend to cause a lack or top end power and still work low down and the mid range.


If there is a fault for boose pressure below spec it needs N75 or associated vacuum pipes.

If there is a fault for boost pressure above spec, it probably needs a turbo.

But with either of those two, it would improve for a short time, every time you turn the ignition off and on again, so less likely.

[heightswitch]

nickd01 said:

My partners A3 (Y-reg) 1.9 TDI has zero power, it literally feels like some one has taken the turbo!

Around 2k revs there is a slight surge but after that it simply gets nosier and no faster! On the motorway with an incline it noticably slows; sometimes to 50/60 on a long incline.

I can hear (I think) the turbo whistling on acceleration but I swear it's not doing anything.

Is there anything I can do to see whether the turbo is knackered? It's not smoking or chewing oil.

Nick

Sounds like a hole in one of your intercooler pipes allowing turbo boost to be lost.
if they are accessible under the bonnet get your missus to rev the engine to 3000 rpm whilst holding the pipes. If they are holed they won't pressurise.

N.

[Tame Technician]

Hadnt thought of that, good point.

But if there is a boost leak, intercooler or other wise, it will smoke like mad out the back, and you will here a loud hiss under the bonnet when it is revved, Louder than the normal turbo noise.

[heightswitch]

Tame Technician said:

Hadnt thought of that, good point.

But if there is a boost leak, intercooler or other wise, it will smoke like mad out the back, and you will here a loud hiss under the bonnet when it is revved, Louder than the normal turbo noise.

Paul.
out of curiosity I have a 2005 (55) A4 2.0Tdi Avant. I am buying a 2005 (05) A3 2.0Tdi Quattro Sport. Both are rated at 140hp. are the engines the same? They look a little different or is this just packaging on the covers etc. I had heard that the A4 is a common rail engine and the A3 is the older direct injection is this true or am i worrying about nothing?

is this anything that should be putting me off the A3? I need the quattro for the winter being 400m above sea level in Northumberland

are there any things I should be looking out for when I go to purchase it next week, it has 54k miles 1 owner car?

Cheers
Neil.

[Tame Technician]

Its basically the same old PD engine in both. Covers are probably different though.

Common rail didnt happen until the latest shape A4 and most recent facelift A3. 2008/2009

A3 has haldex 4wd, not as good as proper torsion 4wd that A4 A6 etc have. But still up to the job of winter driving.

Make sure there is no clutch judder. Make sure there are no warning light on. Make sure the A/C works, never believe anyone who says it just needs a re-gas, they will have tried that already will be leak or compressor.


What can go wrong
2.0 TDI generally, http://www.pistonheads.com/gassing/topic.asp?h=0&a...

How to tell
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by Tame Technician on Sunday 16th August 19:01

[heightswitch]

Tame Technician said:

Its basically the same old PD engine in both. Covers are probably different though.

Common rail didnt happen until the latest shape A4 and most recent facelift A3. 2008/2009

A3 has haldex 4wd, not as good as proper torsion 4wd that A4 A6 etc have. But still up to the job of winter driving.

Make sure there is no clutch judder. Make sure there are no warning light on. Make sure the A/C works, never believe anyone who says it just needs a re-gas, they will have tried that already will be leak or compressor.


What can go wrong
2.0 TDI generally, http://www.pistonheads.com/gassing/topic.asp?h=0&a...

How to tell
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by Tame Technician on Sunday 16th August 19:01

Thanks for that.
I have to say that generally I am over the moon with the smoothness of the 2.0Tdi engine.
mine does suffer from the 1st gear clutch judder and it hates being caught out at a junction in 2nd gear its much easier to stall Apart from that though it is a Rolls Royce in comparison with my Rover 200 turbo diesel. that said the Rover does have 175k miles on the clock and has only ever needed a throttle cable.

i'd put the clutch judder down to soft engine mounts needed to smooth out the old knocker.

its out of warranty now though so i will live with it, to be honest It is only noticeable if pulling away on an incline at lights etc.

How does the haldex system cope? and is it pretty reliable? I do miss my old 2.7 S4 but i need the economy with 100miles per day commute. The problem with where I live is during january. it usually dawns frosty and then snows after I have gone to work making the return home the problem. i really regret buying the FWD A4 and not searching out a Quattro but the plan is now to minimise my market loss by running the A4 for another couple of years before trading it for an S4. in the meantime I am hoping that a low mileage A3 Quattro will serve me well for a few years and give us 1 4WD car for the winter.

N.

[jimmyb]

Very likely to be boost pressure sensor. Sounds almost exactly the same symptoms as mine which was the sensor.

[nickd01]

Thanks for all your replies, I'll start investigating your ideas this week.

I think a Haynes manual will be the first purchase!

[_Batty_]

nickd01 said:

Thanks for all your replies, I'll start investigating your ideas this week.

I think a Haynes manual will be the first purchase!

as above, it will either be the solenoid or the turbo itself...

[DPX]

If the turbo is the same as the vw one try this .
There is a little air operated piston on the side of the turbo that controls the vanes
However sometimes they get stuck .
I found on one a few years ago if you give a good suck on the pipe the control arm should move
about 1/2 inch .
If it does not get under the car and move it to and fro by hand util it frees up
It pays to wear gloves as your hands are going to get black.
Make sure the car has not been run for a hour or so and these bits get very hot.

[Tame Technician]

If the turbo was sticking, it would go into limp home, Doesnt sound like its doing that, It would return to normal after an ignition cycle if it was.

My moneys on Air mas, or boost pressure sensor.

[jimmyb]

Just a quick Q for the op. Did it just suddenly happen or did you notice over a few days that sometimes the turbo would pick up then drop off till it simply would pick up and go at all ?

[nickd01]

jimmyb said:

Just a quick Q for the op. Did it just suddenly happen or did you notice over a few days that sometimes the turbo would pick up then drop off till it simply would pick up and go at all ?

I've only driven it a few times, and it's always been like this. The missus doesn't remember if it's only just started doing it or whether it's always been like it.

Due to my shocking mechanical ability, I might try and find an independent garage within the M25 to have a look at it for us.

[jimmyb]

nickd01 said:

jimmyb said:

Just a quick Q for the op. Did it just suddenly happen or did you notice over a few days that sometimes the turbo would pick up then drop off till it simply would pick up and go at all ?

I've only driven it a few times, and it's always been like this. The missus doesn't remember if it's only just started doing it or whether it's always been like it.

Due to my shocking mechanical ability, I might try and find an independent garage within the M25 to have a look at it for us.

TBH if its the boost pressure sensor then it shoudnt be more than about 80 quid at an audi garage to have it replaced.