A2 TDI loss of boost

[Nathan Barnes]

I hope someone can help!

Travelling home last night on the motorway, I lost all urgency and acceleration (like there was no boost).
I pulled over and switched off. The problem went away for the rest of the journey (which was about 90 miles)

The same thing has happened this morning, only this time a restart only cleared the fault for a minute or so.

When the problem occurs, foot to the floor on the flat is 80mph but as soon as you hit an incline, it struggles to keep to 60mph.

Does anyone have any ideas please? I really need my car to travel a 230 mile round trip to/from work. Up until now, the car has been faultless.

Thanks in advance!

 

[Nathan Barnes]

Forgot to mention that no warning lights come up on the dash.

 

[desertstorm]

You need to check for fault codes, you will probably find one relating to overboost. Could be a sensor issue but quite often it's down to carbon building up in the VNT mechanism meaning the ECU is unable to control the boost levels.
The engine goes into what is called limp mode to protect itself, this is reset when the engine is restarted.
@45bvtc has one of these and suffered similar issues.

 

[45bvtc]

You need to check for fault codes, you will probably find one relating to overboost. Could be a sensor issue but quite often it's down to carbon building up in the VNT mechanism meaning the ECU is unable to control the boost levels.
The engine goes into what is called limp mode to protect itself, this is reset when the engine is restarted.
@45bvtc has one of these and suffered similar issues.

Say thanks to desertstorm for alerting me Nathan Barns and yes I had exactly the problem you describe on my 90bhp TDi Audi A2 and always light throttle; fortunately my local guru diagnosed the issue immediately I gave him the symptoms so off came the turbo and a de-coke undertaken. 2K miles on and the response from the motor is perfect, easier to rev, more flexible down low, and more mpg

It IS a common problem with variable vane turbochargers and that's what you and I have

Here are my before and after turbocharger internals photos:

Basically them fingers foul up and can't move so over-boost occurs and as there's no dump valve the ECU says HELLO and GOODBYE in that order and provide you with 'limp mode'.

I have switched off and back on the ignition and that did for me restore power but unfortunately turned other things off - like the power steering so I'd suggest you do not do the same; and internal turbocharger clean is what you need; it's a common problem I'm afraid...

PS: go see the thread "A2 TDi loss of boost"
1.4 Tdi FAILSAFE Mode
1.4 Tdi FAILSAFE Mode

 

[Nathan Barnes]

Thanks for the prompt reply @45bvtc and @desertstorm.

I have booked her in to a local VAG specialist on Wednesday - We''l have to wait and see!

On this mornings commute, it didn't miss a beat for 100 miles. Strange.

 

[45bvtc]

Thanks for the prompt reply @45bvtc and @desertstorm.

I have booked her in to a local VAG specialist on Wednesday - We''l have to wait and see!

On this mornings commute, it didn't miss a beat for 100 miles. Strange.

Yep, same for me... Initially I couldn't repeat the issue even with 'destertstorm' and his wonder-machinery and knowledge alongside, however, it did continue and eventually more often so just be aware.

My 2054 Reg Audi A2 1.4 TDi (90bhp) car came from a seller with 100% Stafford Audi service (yeah, right...) and when I informed Stafford Audi of the issue and post-resolution they were quite amazed and had zero knowledge even of the complaint/issue - SO BEWARE your Audi dealer...

Putting that into perspective as an Audi RS3 owner I remain AMAZED at how little Audi Master/Super/Mega/Wonder Techs know of on-the-road driving issues with anything... If it ain't in the whatever GmbH destruction book these guys just don't want to know or understand or have any aptitude to do anything other than stick a finger in the left-ear hole.. Sorry...

 

[Nathan Barnes]

Strangely enough, my car has a Stafford Audi history too.....Coincidence

 

[45bvtc]

It is interesting what an Audi dealer does and/or does not do; my A2 was purchased privately but with years and years of Stafford Audi maintenance and a brand spanking new MOT; however, once home, a new set of brake discs and pads front and rear, a new OS headlamp, a new fuel filter, 3-oil and filter changes to get the engine oil to look something like engine oil, and yes it had just had an oil change (?), a new nearside wheel bearing (sooo noisy), and then the turbocharger issue. That said, what a fabulous motor car this A2 1.4TDi 90bhp is! For sure it gets more use than our Audi RS3 and Audi TT roadster put together; other Audi owner drivers need to wake up and see the value and FUN in this Audi A2 motor car - as you obviously have and do...

 

[Nathan Barnes]

On inspection, it looks like the intercooler has a split in it! Phew!

New one on order right now......

Thanks for the help guys!!!

 

[45bvtc]

That's a much easier job, Nathan... The A2's a GREAT car and well worth the effort...

 

[Nathan Barnes]

All sorted now. Back to its former glory.

Its now racked up 130K and still going strong....

 

[Naweed Iqbal]

I hope someone can help!

Travelling home last night on the motorway, I lost all urgency and acceleration (like there was no boost).
I pulled over and switched off. The problem went away for the rest of the journey (which was about 90 miles)

The same thing has happened this morning, only this time a restart only cleared the fault for a minute or so.

When the problem occurs, foot to the floor on the flat is 80mph but as soon as you hit an incline, it struggles to keep to 60mph.

Does anyone have any ideas please? I really need my car to travel a 230 mile round trip to/from work. Up until now, the car has been faultless.

Thanks in advance!

Hello,

I have a very similar problem on my audi a2 tdi only on the motoray and I wondered if you ever found out the problem?

Cheers

 

[desertstorm]

On inspection, it looks like the intercooler has a split in it! Phew!
New one on order right now......
Thanks for the help guys!!!

Check for boost leaks in the hoses or intercooler as Nathan had. look for wet oily patches as this will usually guide you to an issue.

 

[45bvtc]

Hello,

I have a very similar problem on my audi a2 tdi only on the motoray and I wondered if you ever found out the problem?

Cheers

My A2 90bhp TDi was exactly the same. The fault when eventually found was with its Variable Vane Turbo (VVT), and it typically failed on the motorway under light-load; see the thread "1.4 Tdi FAILSAFE Mode." And here's some photos of before and after the vanes were cleaned:



Once done, a 100% fix, no further problems...