Audi A3 Diesel - turbo issue?

A3 1.9tdi '05. on the way home from work yesterday suddenly there was a lot less acceleration. engine still works fine but very slow to accelerate and increase speed. would it be the Turbo? (I do a lot of short commutes in the car as opposed to long driving). is this something most garages would be familiar with? or should I go to a VAG branded one / specialist?

tossy

glasso wrote: »

A3 1.9tdi '05. on the way home from work yesterday suddenly there was a lot less acceleration. engine still works fine but very slow to accelerate and increase speed. would it be the Turbo? (I do a lot of short commutes in the car as opposed to long driving). is this something most garages would be familiar with? or should I go to a VAG branded one / specialist?

It could be a few things but probably not serious. was there any extra smoke when this happened ? My guess would be some sort of boost leak. Any decent indie should be able to help you.

Where are based ?

tossy

tossy wrote: »

It could be a few things but probably not serious. was there any extra smoke when this happened ? My guess would be some sort of boost leak. Any decent indie should be able to help you.

Where are based ?

Stillorgan area. any recommendations appreciated. cheers. it was dark in heavy traffic so couldn't see the smoke...

tossy

glasso wrote: »

Stillorgan area. any recommendations appreciated. cheers. it was dark in heavy traffic so couldn't see the smoke...

Next time you are driving it just look for heavy smoke, should be easier to see if there is a car behind you at night.

I don't know anyone around your area to recommend but i'm sure someone might.

anyone know a VAG knowledgeable independent in the stilorgan, blackrock, dun laoighre, shankhill area or anywhere else nearby?

asteroids over berlin

same thing happened to mine - egr valve, unfortunately in mine it is attached to the cooling fan. You should not drive it and get it checked immediately, I hope it is not the same issue a smine - expensive ! good luck.

I should add mine was a 2010, perhaps the on board chip/computer triggered the lock down on acceleration, can't remember

* Audi sth Dublin service centre is in Sandyford - don't expect favours from em though

asteroids over berlin

asteroids over berlin wrote: »

same thing happened to mine - egr valve, unfortunately in mine it is attached to the cooling fan. You should not drive it and get it checked immediately, I hope it is not the same issue a smine - expensive ! good luck.

I should add mine was a 2010, perhaps the on board chip/computer triggered the lock down on acceleration, can't remember

* Audi sth Dublin service centre is in Sandyford - don't expect favours from em though

yes, I've heard that they are that way.... have only been up there to get some minor parts before.

9935452

glasso wrote: »

A3 1.9tdi '05. on the way home from work yesterday suddenly there was a lot less acceleration. engine still works fine but very slow to accelerate and increase speed. would it be the Turbo? (I do a lot of short commutes in the car as opposed to long driving). is this something most garages would be familiar with? or should I go to a VAG branded one / specialist?

My guess would be the mass air flow sensor might need replacing

9935452

9935452 wrote: »

My guess would be the mass air flow sensor might need replacing

might give it a go at cleaning this first - or at least taking it off to see if it makes a difference.

selectamatic

Were you accelerating when it happened? If so it sounds like a boost leak or ya blew a boost pipe off the intercooler. Did the car sound really loud like a tractor after it happened? Could also be the egr valve which if gone you should look into getting blanked off as they are useless anyways however a remap is usually needed afterwards. The airflow meter is plumbed into the boost system aswell so you will be able to check it while checking all the other issues. To me it doesn't sound like a turbo failure as they are generally more noticeable when they happen as plumes of blue/white smoke will be whaling out the exhaust and you certainly wouldn't have driven home with a failed turbo.

selectamatic

selectamatic wrote: »

Were you accelerating when it happened? If so it sounds like a boost leak or ya blew a boost pipe off the intercooler. Did the car sound really loud like a tractor after it happened? Could also be the egr valve which if gone you should look into getting blanked off as they are useless anyways however a remap is usually needed afterwards. The airflow meter is plumbed into the boost system aswell so you will be able to check it while checking all the other issues. To me it doesn't sound like a turbo failure as they are generally more noticeable when they happen as plumes of blue/white smoke will be whaling out the exhaust and you certainly wouldn't have driven home with a failed turbo.

may have been accelerating at the time yes. no tractor sounds or big smoke... so that makes it more likely a boost pipe or leak if it happened whilist accelerating? haven't got it attended to yet... car works ok still just low power and awful acceleration....

selectamatic

Boost leaks generally start whilst the engine is under load and the turbo is spooled up and thus boosting. In the case of vag cars it's not unheard of for a boost pipe to be blown clean off the intercooler as they really aren't a great design and the plastics deteriorate slightly with age. All told though they're not too complicated and problems should be easily diagnosed by a mechanic, since there was no major smoke or noise I can't see the problem being too major. There's a boost sensor on the intercooler which puts the car into limp mode when the turbo is over boosting due to a lack of back pressure within the boost system so it's likely that your car went into this limp home mode due to the problem.
Check all boost lines first for leaks
check the intercooler itself for leaks
Check the maf
And finally the egr valve
It's most likely one of the above.
If it's a boost leak the car may start boosting again if you turn it off and on again however it will return to limpmode the minute the turbo exceeds it's peramiters (over boosts) it will return to limp mode.

jca

selectamatic wrote: »

Boost leaks generally start whilst the engine is under load and the turbo is spooled up and thus boosting. In the case of vag cars it's not unheard of for a boost pipe to be blown clean off the intercooler as they really aren't a great design and the plastics deteriorate slightly with age. All told though they're not too complicated and problems should be easily diagnosed by a mechanic, since there was no major smoke or noise I can't see the problem being too major. There's a boost sensor on the intercooler which puts the car into limp mode when the turbo is over boosting due to a lack of back pressure within the boost system so it's likely that your car went into this limp home mode due to the problem.
Check all boost lines first for leaks
check the intercooler itself for leaks
Check the maf
And finally the egr valve
It's most likely one of the above.
If it's a boost leak the car may start boosting again if you turn it off and on again however it will return to limpmode the minute the turbo exceeds it's peramiters (over boosts) it will return to limp mode.

What's "back pressure within the boost system" supposed to mean? There's either pressure or no pressure..

jca

It sounds to me like the dreaded sticking turbo vanes problem. If there's an over boost fault logged that's your problem.

selectamatic

jca wrote: »

What's "back pressure within the boost system" supposed to mean? There's either pressure or no pressure..

Well if we're being pedantic you're right it's not back pressure but it's a term that's used by a lot of people to describe the conditions we are talking about within the boost system. When there's a sizeable leak the turbo spools too quickly and too freely therefore the sensor cuts in and the car goes into limpmode. When the system is pressurised the turbo spools normally and all of its psi is utilised by the engine.
Idk really would it be sticking turbo vains that tends to be a more intermittent problem that gets progressively worse. The ops problem was more sudden and pronounced.

Waterson

The symptons you describe are almost certainly the result of the car's computer being in a imited operation startaegy (or limp-home mode. The engine computer will limit the power output of the engine as it has recognised a fault with a critical sensor or faulty actuator. As above you can speculate all day long as to the cause, but what you need is a diagnostic plug in to discover the cause. Is your engine management light on?

jca

selectamatic wrote: »

Well if we're being pedantic you're right it's not back pressure but it's a term that's used by a lot of people to describe the conditions we are talking about within the boost system. When there's a sizeable leak the turbo spools too quickly and too freely therefore the sensor cuts in and the car goes into limpmode. When the system is pressurised the turbo spools normally and all of its psi is utilised by the engine.
Idk really would it be sticking turbo vains that tends to be a more intermittent problem that gets progressively worse. The ops problem was more sudden and pronounced.

There's so much wrong with this post it's laughable. You obviously don't know the difference between airflow and air pressure. Op get the codes read as another poster rightfully said it could be anything from a dodgy accelerator pedal to a busted pipe.

selectamatic

jca wrote: »

There's so much wrong with this post it's laughable. You obviously don't know the difference between airflow and air pressure. Op get the codes read as another poster rightfully said it could be anything from a dodgy accelerator pedal to a busted pipe.

Yay another pointless argument on the motor section of boards.
What I said will make perfect sense to anyone who has experienced such boost problems. If the turbo exceeds it's parimiters the sensor on the intercooler puts the car into limp mode. This most commonly happens when the boost pipes are leaking or the intercooler itself is leaking boost pressure. Don't see why you're bringing up the differences between airflow and pressure.

jca

selectamatic wrote: »

Yay another pointless argument on the motor section of boards.
What I said will make perfect sense to anyone who has experienced such boost problems. If the turbo exceeds it's parimiters the sensor on the intercooler puts the car into limp mode. This most commonly happens when the boost pipes are leaking or the intercooler itself is leaking boost pressure. Don't see why you're bringing up the differences between airflow and pressure.

What you're saying doesn't make perfect sense at all and I had the very same intermittent loss of power as the op is getting. It was diagnosed after the codes were read as an implausible signal from the accelerator pedal which was cured for about 9 months after replacing the pedal. The power loss returned again and this time the overboost code was flagged I'd had enough at that stage and got rid enough was enough...

selectamatic

I never said the op's problem was most definitely a boost leak issue, I merely suggested it could be.
Boost leaks causing the car to go into limp mode is however a common problem on vag 1.9tdi engines and it is a much more common problem than the accelerator issue you put forward.
Now again I'm not saying which problem it is as anyone's guess here is as good as anyone else's, what the car needs is diagnostics. But I still don't see why you felt the need to berate me for putting forward a very common problem as a possible cause.

in the end, I took out the mass airflow sensor. cleaned it with isopropyl alcohol. power is back as before. could be down to the air filter - will change that in short order.

There was no engine management light on. I bought a cheap u480 odb reader (10 euro or so from ebay) and that threw up nothing so just tried cleaning the sensor (youtube shows you how to take it out without needing the VAG torx tool).

Waterson

Thanks for the update OP, glad you resolved the problem. Interesting that the fault code reader didnt log any MAF codes, would have expected something with those symptons.