2004 TDI 90 Sudden loss of power. Limp Mode/Warning Light?

chriscddj

chriscddj

Member
I have a constant issue with my 2004 TDI 90 on long runs. There is a particular hill on the A64 near York where the engine warning light comes on and I notice a huge loss of power. This can only be remedied by pulling over, switching the engine off and then back on again and it's fine again. I've had the car in at my local garage. I printed off the thread from here about the overboost caused by a leaking or damaged boost pipe but they have said that they have checked all the pipes and can't find anything wrong. No splits or anything loose. They have suggested putting a few bottles of Redex System cleaner through it to see if it helps but failing that they have said the turbo could need replacing. I don't mind replacing the turbo but what I'm worried about is spending all that money to then find out the problem remains. It's doing my head in to be honest and it's so dangerous being in the outside lane of a motorway to suddenly get a huge loss of power. Any help would be greatly appreciated :)
 
I'm not sure which thread you printed off but in addition to pipe leaks there are also potential problems with sticking turbo vanes (only) on the 90 tdi's, blown end tank seals on the aftercooler and faulty MAP sensors.

If your local garage is a bit out of it's depth Darkside Developments may not be too far from you and seem to know there stuff on TDis - http://www.darksidedevelopments.co.uk/our-unit/
Having said that, I'm not aware of any A2oc members who have used their services.

Cheers Spike
 
Hello Chris - welcome to this great club,

I would suggest getting the car scanned with VCDS, not a generic scanner, and see what fault-codes are registered before going down the route of replacing anything.

Your car appears to be going into limp-home mode, and a fault code will be logged.

There is a social meeting on 22nd May, and you'll probably find someone there who can scan and troubleshoot the issue for you - link below
http://www.a2oc.net/forum/showthrea...kshire-Sunday-22-May-2016&p=250684#post250684

Cheers
Jeff
 
Hi Chris, and welcome to A2OC.

I've sent you a PM with a suggestion, but those above are also good. Your car will be going into limp mode either due to over boost or under boost. As Jeff says above, a diagnostic scan will help to establish which. There are all manner of reasons why the car could be over- or under-boosting, especially given that the TDI90 is fitted with a variable vane turbo. I would be highly reluctant to replace the turbo unless I had firm evidence that it was the cause of the problem. All other possibilities ought to be explored first: vacuum piping, the boost air pathway, the MAP and MAF sensors, etc.

I have so far had only limited experience of Darkside Developments, though it's been positive. Their VAG TDI knowledge is probably unbeatable because they work on nothing else, but the A2 as a model may be something of an unknown to them.

All the best,

Tom
 
Thanks for the advice guys this is very helpful. If it was sticking turbo vanes would the Redex System cleaner stand a chance of fixing it or would that not work? Sorry to sound thick I wish I knew what I was talking about. Although I fully trust my garage and they're nice chaps I felt like they were a bit annoyed when I showed them a thread from here. On Monday morning I drove from Wakefield to Whitby and as I approached the dreaded hill I put my foot down and like clockwork the warning lamp came on and I dropped from 70mph to 25mph in about 200 yards. I pulled over switched it off, left it a few seconds, restarted and the warning lamp disappeared and back to full power again.
 
Hi Chris,

Everything you describe verifies that the car is going into limp mode; that switching the ignition off and back on again temporarily cures the problem makes sense.
Whilst I've no doubt that your garage guys are nice, trustworthy people, that doesn't mean they know anything much about A2s. As professional mechanics, I can imagine they might have been somewhat irked by being pointed towards a group of online enthusiasts. However, as an A2 owner, the greatest difficulty is finding people who have some model specific knowledge. Luckily, you've come to the right place.
I would be greatly surprised if a dash of Redex cured your car's issues, though if it's a low-cost experiment, you could give it a go and cross your fingers.

Again, unless we know whether it's an over-boost or an under-boost issue, it's difficult to start offering advice that's not simply speculative. I'd be more than willing to give your car a diagnostic scan as that'd really help to get the ball rolling, but I'm about to embark upon an A2-themed tour of the southern reaches of this island so won't be available for the next week or so. I've then got a fairly big job in Ripponden starting on May 9th. If you can hold off until then, I'll happily take a look at the matter.

Cheers,

Tom
 
I agree, same here, same symptoms, exactly. I had the turbo removed and the vanes cleaned and now ALL is OK, even better

Before and After pics

P1020244_Before.jpgP1020253_After.jpg

Have to say, car is soooo way better after the vanes are cleaned so don't despair
 
Special edition said:
Has anyone ever used "revive turbo cleaner and restorer" ?.
http://www.ebay.co.uk/gds/Turbo-Charger-Cleaning-Power-Restorer-/10000000179109699/g.html
Click to expand...

No, but someone on the forum use a similar cleaner made by Ecotek - http://www.ecotek.eu/power-boost/ and it did not work -
http://www.a2oc.net/forum/showthread.php?15638-EGR-Valve-Bypass-Stealth-Racing&p=118635#post118635

Since its sprayed down the intake then goes through the diesel combustion process it's unlikely to have much cleaning power left to tackle the baked on carbon in the exhaust side of the turbo.

Cheers Spike
 
I've managed to find a local garage that specialise in Audi and VW's so I'm hopeful of getting this problem sorted. When I described the problem he knew instantly what I was talking about and said its a common fault. So yeah fingers crossed. I'll let you guys know the outcome and costs involved etc.
 
Hi Cammy,

As soon as I have an outcome I'll let you know. I've actually learned to drive around the problem now as I can predict exactly when and where it will happen. Due to work commitments and various other things going on I don't have time to get under the car myself so I'm having to get it fixed by the garage.

Chris :)
 
It most certainly IS a common fault with variable vane turbochargers - 90bhp A2 - especially where the car has been used generally on local runs and 'cheap' fuels - it's just carbon build up; get it cleaned properly and you'll be amazed at the difference - from experience. Great cars.... Good luck
 
Hi Chris,

Would that local garage happen be German Autocare by any chance ?. The reason i ask is that ive been there a couple of times and so have other club members - not such a cheap hourly labour rate but they do appear to have a reasonable knowledge our A2,s. My car goes into limp mode but there is a gap of around 3 months in between occurances and its only when i start journeys. I would be interested to know the outcome too !.

Ta
Dave
:)
 
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It could be my fuel I always fill up at Asda as it's close to my house but I've always wondered what the quality of the fuel is like. My car is generally only used on long runs my drive to work on a Monday morning is 80 miles and then the same journey home on Tuesday night. So it does get regular decent runs. My A2 has done 108000 miles and the vanes have never been cleaned to my knowledge so the build up of carbon is probably pretty bad. The only good side to the problem is because I'm driving it so carefully I'm averaging around 70mpg at the moment and that's on winter tyres
 
chriscddj said:
Hi Cammy,

As soon as I have an outcome I'll let you know. I've actually learned to drive around the problem now as I can predict exactly when and where it will happen. Due to work commitments and various other things going on I don't have time to get under the car myself so I'm having to get it fixed by the garage.

Chris :)
Click to expand...

I could do that, Chris, I could drive around the problem and predict failure; I could even switch-off and back-on again while motoring - not to be recommended - and that in itself said "turbo vanes sticking" and the ECU acknowledging that fact with a simple 're-set' and proving it was not a hose or inter-cooler failure; a turbo strip and clean sorted the issue 100%
 
Special edition said:
Hi Chris,

Would that local garage happen be German Autocare by any chance ?. The reason i ask is that ive been there a couple of times and so have other club members - not such a cheap hourly labour rate but they do appear to have a reasonable knowledge our A2,s. My car goes into limp mode but there is a gap of around 3 months in between occurances and its only when i start journeys. I would be interested to know the outcome too !.

Ta
Dave
:)
Click to expand...

Hi Dave,

It's Allanson VW & Audi Specialists. I've not used them yet though so I'll let you know how it goes. I have heard good things about German Autocare too.

Cheers,
Chris
 
Is it Peter Allanson at Newton Bar or his son Steven Allanson at Agbrigg - Ive known them both for many years. Steven,s very reasonably priced and he,s worked on Audi,s for 35 years. He used to service my VW Beetle in the early 80,s. :)
 
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chriscddj said:
It could be my fuel I always fill up at Asda as it's close to my house but I've always wondered what the quality of the fuel is like. My car is generally only used on long runs my drive to work on a Monday morning is 80 miles and then the same journey home on Tuesday night. So it does get regular decent runs. My A2 has done 108000 miles and the vanes have never been cleaned to my knowledge so the build up of carbon is probably pretty bad. The only good side to the problem is because I'm driving it so carefully I'm averaging around 70mpg at the moment and that's on winter tyres
Click to expand...

80-miles is a good run and 70-mpg is brilliant, like wow!, but maybe that's part of your problem as engines do like to be worked - try it and see how much soot comes out the exhaust, a good indicator (mine did when purchased second hand (was a local runabout) and for sure it don't do it now...); maybe worth considering an additive (Millers, Redex) every other tankfull; I do this to both my diesel and petrol cars, just keeps everything clean on the insides...
 
UPDATE: The turbo vanes are not the issue apparently they are spotless and the turbo itself if working perfectly. Steve said he's never driven an Audi A2 with so much power. He's cleaned out a sensor that seemed to be particularly dirty but apart from that he's told me to see how it goes and get back to him. I guess it's just a case of taking it one step at a time.
 
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