A3 TDI Intermittent Power Loss

[sharkhandler]

Hi all,

my car - 2001 A3 TDI 110 sport.

A couple of years ago I was driving my A3 really hard, I was accelerating in 3rd gear at about 3500 rpm and I felt as if something 'snapped' in the car. I lost all power and with my foot stamped hard to the floor, I was getting no torque at all, but the car was still moving forward. I thought I'd blown my turbo.

The next day it was fine and it was fine for the next couople of weeks, then it went again driving to work, but by the end of the day it was fine again.

My car has struggled like this for the last couple of years. Audi, on a guess, fitted a new Air Mass Meter in February (that's the MAF, right?) and initially it made a difference.

Until that is we had that period of cold damp weather about a month ago, and every day I would lose power - but I couldn't put my finger on where: sometimes it would be when I was accelerating hard in 2nd gear at 3500rpm, the engine would just go limp; other times I would be able to go hard through the gears then at 70, in 5th at about 3000rpm, it would just go limp. I would switch off the engine, leave it for a couple of hours and it would either show the same problem, or it would be fine – I guess depending on how cold or damp it was.

To make matters worse, now that we've had hot dry weather recently, the car had behaved perfectly - I can floor it all the way through to 80 and the car behaves like a dream.

I'm about to take my car back to Audi, and I don’t want to be told 'you need a new turbo' because it sounds like something feeding the turbo is bust - I've read about MAP sensor, N75 valve, EGR vale - but WHY does it seem to be temperature dependant?

Any ideas - this is driving me nuts (no pun intended)

Paul

 

[banny]

my friends Bora was like that, turned out to be the turbo, as they full up with crud in the vanes, causing overboost failiures.
Have you put the car on Vag-Com to see if it throws up any errors.
Does it do it more under load, my friends used to do it more when climbing hills.

 

[sharkhandler]

thanks for your reply,

so it could be the turbo? ******. Is that a full replace or can they be cleaned out?

But again, it was werid that when it blew it was when it was being worked hard, then there's intermittent loss of pwer afterwards.

I've not noticed any load related issues - this is on simple driving to work and back on flat straight roads.

I haven't bought a USB interface for my laptop yet to try VAG-com. DO you know where can I get them?

 

[banny]

The vanes on the VNT mechanism get clogged up, they can be cleaned.
http://forums.tdiclub.com/showthread.php?t=140910

http://pics.tdiclub.com/data/500/Drivbiwire_VNT_repair_procedure_small.pdf

Dont take this as gospel that this is the problem, but it is common on those turbos.
For Vag-Com try here
http://www.ross-tech.com/products.html

 

[sharkhandler]

hi banny,

great article, thanks - but it just does not make sense - if the valves were clogged then the car would be sluggish all the time. This morning, I absolutely nailed the car - dropped it into 3rd gear at 60 and took it to 4000rpm + , and the turbo behaved beautifully. If I had tried that a month ago when it was cold and damp, well I dread to think what would have happened.

 

[banny]

My mates 115 PD Bora was not sluggish all the time, you do really need to get the car on a VAG-COM, then give us your fault codes and see it throws up an overboost fault, have you tried wriggling your VNT mechanism to see if it is tight or not, should be a little stiff to begin with but have a decent range of movement.

 

[Morbs]

Hi, new on here hope someone can help. I have an A4 tdi 130 which is suffering from power loss at 1800rpm, only when you accelerate hard, it makes the gear stick vibrate foward and backwards fast and feels like it has to much fuel going in as there is no pick up on speed. Have changed the temp sensor and today the maf but its still the same. car has done 133k with full history. anyone want to buy it???

 

[bham a3]

Hi, I have a Audi A3 1.9 TDi 2001 aswell. In the morning my car seems to loose all of the boost for the first couple of mins but after that the boost comes back. The weather isn't the best at the moment, would this of contributed to the problem? On the way home tonight I lost all boost and it was up a hill aswell, it seems like the boost like to come and go. This seems like the turbo is on its way out, am I correct? Is there anythink that I can check to see weather the turbo is on its way out? Can someone please comment on this as I dont want to take it to a garage if I dont need too.

 

[moschino]

Paul,
Maybe the inside of your CAT is blocking the exhaust? Do you get a strange rattle at certain revs?

My CAT fell apart from the inside, in the end I was only able to do 30MPH, had to stop and whack the cat with a hammer to free up the blockage to get going again.
In the end I removed the cat and smashed out the inside, it was the same size as a tennis ball and as such blocking the exhaust.

Runs fine now, passes the MOT no problems, gives you a few more BHP as well.

Just a thought......... Especially if you have tried the other fixes!
Jim.

 

[fjtwelve]

On my old 1998 Passat 1.9TDi 110hp these symptoms were cured by replacing the temperature sensor (£15) after a certain Edinburgh VW garage that is no more said i needed a new turbo (£1100). A bit later the MAF was replaced too (exchanged £75). Had done from memory about 110,000 miles at that point. My current A6 2.5TDI is showing similar symptoms and i will be having the sensor replaced at the next service 4th April. Will try to remember to post here if it fixes it.

 

[dobbin]

I have recently experienced what sounds like a similar issue, here is what happens if you dont fix it :

My Car : 2004 A3 2.0TDi (140). Exactly as per the first poster I would loose power under load. I would turn the car off (usually whilst coasting), then turn it back on and all would be well. No engine lights no nothing. Reading the fault codes pointed towards this MAF thingy. Had that replaced and as per above, it did get better, but not much, until one morning it lost all power accompanied by plumes of white smoke.

Like an idiot I tried to key it again, and it ran - lumpy, and then stopped. No oil in engine. The turbo had failed sucking the oil out of the sump and into the exhaust/air intake. This got into the cylinders and the engine was unable to compress the oil in the top of the cylinder. Needed a new head and turbo.

Incidentally, when it went to be fixed, the man reckoned he had done a few with exactly the same problem. Which is nice.

 

[evobaz]

On my old 1998 Passat 1.9TDi 110hp these symptoms were cured by replacing the temperature sensor (£15) after a certain Edinburgh VW garage that is no more said i needed a new turbo (£1100). A bit later the MAF was replaced too (exchanged £75). Had done from memory about 110,000 miles at that point. My current A6 2.5TDI is showing similar symptoms and i will be having the sensor replaced at the next service 4th April. Will try to remember to post here if it fixes it.

What temperature sensor did you replace?

My 2000 Passat Tdi has started to run sluggish tonight (according to the missus) and i'm trying to find what could be wrong. The Air Mass Meter was changed about 2 years ago. I'm hoping it is the air mass meter again as i may get it changed under parts warranty.

 

[fjtwelve]

Aargh now you're asking this was in about 2002. Erm was near the bottom of the front of the radiator. Can't remember the part name. VAGCOM should show it up, post on the VAGCOM board and see if anybody local will check it for you for a few pints. Sometimes clearing the fault codes fixes it if you're lucky.
Was it a new MAF or a recon on exchange - the latter do not last as long. Checking the MAF is easy - unplug it - no difference to sluggish performance, its probably the MAF. Unplug it - gets worse - its probably not the MAF, try some of the following: clean the MAF using say Halfords brake cleaner; EGR needs cleaning out; N75 valve failed (turbo boost control, accompanied by black smoke as a symptom); blocked fuel filter/air getting into fuel pipe; leaky or blown off turbo pipes or vacumn pipes; manifold pressure sensor or leaky manifold hose; sticking turbo wastegate; blocked crankcase breather filter (accompanied by white smoke); broken cat convertor; dirty/broken electrical contacts in accelerator control/ cruise control......enough already.
Find an independent VW garage, always better. Alternatively Skoda are cheaper but the same engines and parts. And my Passat always ran noticably better and more economically on Shell V Power than anything else, some supermarket stuff was not good and caused a noticable drop off in performance

 

[ruffrida]

Did you ever sort this, be nice to know as its an ongoing problem for my 2000 A3 TDI???

 

[kiporusi]

Is anybody still here?!

I have an audi A3 2001 and 2 days before when i was driving i figure out that my car have loos power.

I read everything here and google it and i have done the follow:

Check MAF is OK because when i take it out the acceleration rise slow.
Check the vacuum is ok also the valve of turbo and egr is ok i check them directly from battery and the vacuum directly on main vacuum tub.When i create vacuum with mouth work everything ok.
Chek MAP is ok clean it.
I have got an diagnostic OBD Autocom and there is no error register before even after i clean errors i take a ride no error the car still no full power.

I have seen the turbo and egr valve when i push acceleration until 2000rpm the start opening then when it need more power both of them close automatically.
I have read about LIMP mode i don't know what to say about it i don't want to mess with that because some of them just want to sell some tools.

Please any idea any suggestions.

Thank you.

 

[Rii91]

Was the issue resolved? What was the problem?