A4 tdi broken turbo?

[superslowtdi]

:1zhelp:my 1996 a4 tdi seems to be down on power, with no kick at all from the turbo. I have replaced the maf sensor from french-german-sweedish and it has made no differance at all. Any ideas where to look next?? any help would be great Thanks

[onzarob]

you need to get a fault code reader on the car and find out what has been logged, anything else is pure guess work :)

[superslowtdi]

ok thanks, might go back to horse and cart.

[onzarob]

ok thanks, might go back to horse and cart.

Unfortunately a horse really has a mind of its own;):biglaugh:

[superslowtdi]

would be one horse power more than i have now tho

[I_am_stealth]

You have to give more details about your car, engine, etc.
If you have the non-VNT turbo ( 90 HP engine) then chances are very small that there is something wrong with your turbo.
You could have a hole in a post turbo hose. CHECK ALL THE HOSES!!
I think you are running into limp mode.
If you scan it with a diagnose interface, it will be a lot quicker.

[ini]

Check that the N75 (wastegate control valve) is working, and all the control hoses are ok (no tiny leaks).

Also check that the wastegate is not full of oil.

[BrendanMC]

I have a 1997 110bhp model with engine code AFN, and i'm on my third turbo in a year, in fact had the car for a year, third turbo since August, now I've realised it's my car that's the problem not dodgey turbos.
So if anyone can help me, you may cure two problems at once.

[I_am_stealth]

I can give you a very simple explanation why you may kill 1000 turbos on a car! If the oil pipe that brings oil from the engine to cool the turbo is blocked, or partially restricted, then you can replace them one by one....It is just an idea, I have no reasons to think this is exactly what has happened to you, at least not yet.
Please give more details on how they "died".

[BrendanMC]

Hi, thanks for the reply, but the bearings didn't go, the turbo is sticking, ie sooted up. Therefore my car must be omitting too much soot, yet it's not overly smokey.
Brendan

[I_am_stealth]

A sticky turbo is NOT a dead turbo.
The ECU will detect high boost, then put you in limp mode to protect the turbo from damage. Secondly, you can easily clean it with a bit of skill.
To tell you the truth, I have been driving with a hole in a tappet for more than 15 000 miles. The valve was opening half way or less. I hardly noticed a difference in fuel consumption. I had a hole in a hose post turbo. I was getting limp mode and black, VERY black smoke. Again, I could not see a large difference in fuel consumption.
I'd be curious to know how you drive, when you change gears, etc.
If you under rev it, or drive too much at constant speed, you might get your variable geometry dirty v easily. Your vanes need to move full range every now and again ;) ...
Maybe your EGR has something to say, maybe your temperature sensor or maf/map report wrong values, therefore injection amount is wrong. Have you ever diagnosed it with something like a VAG-com interface?
Has it been remapped?

[BrendanMC]

Thanks for your reply, ckeaning it I know, this is the third turbo since August. I do have Vag com, no faults recorded. the variable veins are just sticky and i must admit I very rarely take her beyond 2500 revs. Last night i removed the EGR valvw which seem to be in good order, not very dirty and working fine under vacuum, but the port on the inlet manifold was pretty clogged up with grud, not closed over but maybe reduced by 30%- 40%. So we'll see if this makes a difference and i'll give it a boot from time to time, MAF, Airflow meter and inlet temp sensor, water temp sensor all changed less than 10k ago.
Brendan

[I_am_stealth]

Well, if you have VAG com you can easily check your sensors.
I would imagine that 30% clogging of your inlet manifold will hardly make any difference. After all you are telling me there are only three things that I have in mind that can kill your turbo. Your variable geometry, wrong air:diesel ratio and the oil pipe to the turbo.
There must be a value that you see with VAG com which is not OK. Maybe you did not notice it. Email me some of the logs for your engine. I will have a look at them. Alternatly, I live in Leeds, I could try to have a look at your engine one day.
If your variable geometry gets dirty so quickly, there must be a reason for that to happen.

[layerz]

Interested to see how much the inlet cleaning helped if you could let us know.

[I_am_stealth]

Also, is there a chance that there is oil in your intercooler/pipes from your previous turbos dying? You can easily clean that with detergent and water. You might have to take out the intercooler to make your life easier if you are going to do that. That might clog your variable geometry.

[enters]

Hi, thanks for the reply, but the bearings didn't go, the turbo is sticking, ie sooted up. Therefore my car must be omitting too much soot, yet it's not overly smokey.
Brendan


Hi i have a similar or same problem with my 99' A3 110bhp, yet it shows a small sign of boost in 1st then it all dissapears and revs for nothing.
Had suggests of maf sensor but have dissconnected and it shows a small rensponse drop. any help i'd be gratefull.
what about EGR Valve? apparently if blocked or on can result in lose of power.

enters

[I_am_stealth]

Are you not running in limp mode? Try carefully to stop and start the engine for a split second while running. Be VERY careful where you do this and how you do it. If you start getting boost for a bit, you were in limp mode. It is then turbo related.
If the maf is indicating a low value, than injected amount would be low, therefore no power. If you unplugged the MAF and there was no significant difference, the default value then should give you decent power at low revs at least.
You can easily check if the EGR is always open. On your model I believe there are 4 screws that you need to undo to take it out.
If you have a VAG com tool you can easily check all these.

[superslowtdi]

i changed the oil i use to a much thinner oil and now the turbo works!!!! ODD!!!!

[I_am_stealth]

Good. What oil were you using before?

[superslowtdi]

turbo problem fixed!!!! what the hell, been driving my car for 9000 miles in limp home mode as no money to fix problem. used 15-40 oil instead of 10-40 and problem solved instantly!!!!!!!!!!!!!!!!! used cheap brand of oil (£7 for 5 litres) instead of the usual £25 for 5 litres. it looked really thin when i poured it in and hey presto it worked!! turbo kicks in at 2100 rpm and pulls up to 100mph no problem. typical as i advertised the car on ebay earlier in the morning!!