Turbo [A4 tdi]

derossi

Having an issue with my turbo. A4 tdi. Under hard acceleration the turbo dies out. Mainly in low revs. Have to restart the car for it to work again. Doesn't have any of the more classic symptoms and had a car electrician take a look and he found nothing. Before I take it to a mechanic, any ideas on what it could be?

Tony Beetroot

Had your car electrician any diagnostic tools bar googling on his phone?
Car is going into limp mode, sensor issue maybe.

derossi

He is very good, but not good enough it seems. He has all the required equipment. He said he could find nothing. It's not limp mode as such, car continues on but without the turbo. Can still get it up to 60 but takes a bit longer.

George Dalton

derossi wrote: »

Having an issue with my turbo. A4 tdi. Under hard acceleration the turbo dies out. Mainly in low revs. Have to restart the car for it to work again. Doesn't have any of the more classic symptoms and had a car electrician take a look and he found nothing. Before I take it to a mechanic, any ideas on what it could be?

What classic symptoms would those be?

What year is your A4 and which engine does it have?

derossi

I guess the classic ones that pop up all over google like the whistling noises or grinding sounds etc. Not the issue I have hence why I am here. I don't know anything about cars so please excuse my ignorance.

It's a 2003 and 1.9. Not sure what you mean by engine?

Tony Beetroot

Is your car limited to a certain rpm?

beanie10

Does engine warning light come on? Could be leak in boost pipes or inter cooler but engine light would normally come on for that.

derossi

Tony Beetroot wrote: »

Is your car limited to a certain rpm?

Good question, never looked at it but as you can imagine it is very sluggish. I can still get the speed up but it takes a bit of time. I can reset it by turning it on and off.

derossi

beanie10 wrote: »

Does engine warning light come on? Could be leak in boost pipes or inter cooler but engine light would normally come on for that.

No engine lights. Basically when I put the car under pressure, for example up a hill and I floor it in third. The turbo stops and I lose power. If I keep it to more gentler acceleration or accelerating in higher gears/lower revs it seems to be ok.

Special Circumstances

A complete amateur guess here, but it sounds like "classic symptoms" of sticking turbo vanes and overboost leading to limp mode?

George Dalton

Special Circumstances wrote: »

A complete amateur guess here, but it sounds like "classic symptoms" of sticking turbo vanes and overboost leading to limp mode?

That's what I was thinking, the symptoms are pretty indicative of that.

It could also be other things though, should be an easy diagnosis for someone who knows how these systems work and has the equipment required to diagnose.

Tony Beetroot

Unlikely its sticking turbo vanes imo, interesting to hear the outcome.

Special Circumstances

Tony Beetroot wrote: »

Unlikely its sticking turbo vanes imo, interesting to hear the outcome.

Why - out of interest like, rather than looking for a confrontation!

When I joined up boards first, all these threads that get hidden away in DIY were in the main forum and it was a great way to learn common issues/fixes. Always like to learn from people with more experience - the "sticking vanes + limp mode" was a common enough issue I thought - what makes it unlikely in this case?

George Dalton

Tony Beetroot wrote: »

Unlikely its sticking turbo vanes imo, interesting to hear the outcome.

Seems to have the usual symptoms of sticking vanes.

Still could be a number of other things though.

jca

Tony Beetroot wrote: »

Unlikely its sticking turbo vanes imo, interesting to hear the outcome.

What do you think it is? Sounds like sticking vanes to me. A scan with vcds will probably return an over boost error code.

Tony Beetroot

A crankshaft speed sensor would cut it down on power, we can be guessing till the cows come home.
Even a cheap scanner should indicate where the problem lies.

Special Circumstances

Tony Beetroot wrote: »

A crankshaft speed sensor would cut it down on power, we can be guessing till the cows come home.
Even a cheap scanner should indicate where the problem lies.

Oh yeah, I realise there's alternative explanations, I was just wondering for my own knowledge was there something specific pointing in a different direction for you. More of a gut feeling / previous experience thing so rather than X indicates Y (or rules out Z).

derossi

Thanks for all the comments. I can bring it to the guy again and he can scan it? I'll post the codes here.

George Dalton

Did he not scan it the first time?

Did he not give you any indication of what he thought the fault might be?

derossi

George Dalton wrote: »

Did he not scan it the first time?

Did he not give you any indication of what he thought the fault might be?

Aye he did scan it. He said he could not find anything. To keep an eye on it and get back to him if it continues.

Buford T Justice

If its a V G Turbo, which is likely is then it sounds like sticking vanes to me, thus the limp mode.

derossi

Buford T Justice wrote: »

If its a V G Turbo, which is likely is then it sounds like sticking vanes to me, thus the limp mode.

http://www.audi-sport.net/xf/threads/1-9tdi-sticking-turbo-vanes-fix-with-pics.177333/

Something like that?

9935452

Reading this my first thought is mass air flow sensor

debabyjesus

Ask your mechanic to take off the actuator arm and move the vane mechanism by hand. It'll be fairly obvious if its rough or moving freely. Should only take a few minutes.

https://www.youtube.com/watch?v=Ppif4qC560U

Of course your first port of call is a vcds scan.

derossi

Just thought I should update this incase anyone else has similar problems. Because of work I have only got round to sorting it. I returned to the same fella and he found out what the issue is. He said that the pipe between the turbo and intercooler had bust. Part costs 100 Euro. So all is well! Thanks for your help.

derossi

Tony Beetroot wrote: »

Is your car limited to a certain rpm?

Again, just to get a full response. Normally when I got to 3000 rpm it died. I could normally shift up or down and it would sort itself.

derossi

beanie10 wrote: »

Does engine warning light come on? Could be leak in boost pipes or inter cooler but engine light would normally come on for that.

Yeah, just on this. No engine warning light at any time. Just the mechanical issue.

Hope no one minds. Trying to give a full answer incase it pops up again.

derossi

George Dalton wrote: »

Did he not scan it the first time?

Did he not give you any indication of what he thought the fault might be?

He did scan it. He said all it said was performance issues. I have to take his word for it. When I returned I imagine he had a proper look. ?

Polo_Cluvie

I had exactly the same problem on a 03 octavia and it was the turbo. I'd a 09 caddy tdi with similar problem but very intermittent. It took turbo specialist 3 days with 1000s of euros worth of diagnostics to eventually diagnose the turbo. He had to drive it with the diagnostic plugged in to figure it out.