Another .... turbo and loss of power, please can you help?

[Chris_Hardy]

I wonder if anyone could help? As I have the similar problem on this forum (searched 17965 change pressure on google) ,,, having recently purchase a Seat Leon 1.9 tdi the 90 bhp. Basically the turbo cuts out at speed (normally motorway driving) but on A roads as well and seems to loose a lot of power and acceleration. Once the car is parked it seems fine the next time it is driven until the power drop again. Now I have a lack of confidence to over take or to change into the fast lane as I know as soon as I get to the 3000rpm mark the power could be pulled beneath the rug of a good car!
With this problem I have seen a friend with a laptop and cable and have received the sad news of the following error code,
17965 - Charge Pressure Control: Positive Deviation p1557 - 35 - 10 intermittent.
Any help as I have looked at all the vacuum pipes and the sensor and they all seem to be connected. I even looked at the EGR butterfly valve as I wondered if this would cut the turbo off.
What are the VNT vanes sticking inside the turbo? Can I clean them myself??
If this is a senor problem which one of the sensors should I start with? Would really like to get this problem solved.

 

[Black TDI Turbo]

Most likely be the vanes sticking inside the turbo due to carbon build up, needs either turbo stripping and cleaning, (not an easy task to do yourself unless ur very confident as turbos can spin in excess of 200,000rpm), a recon'd turbo, or remove turbo and send away to be recon'd.

 

[Chris_Hardy]

thank you for a quick reply, How much would a recon'd turbo cost? plus how to fit?

 

[funkmonkey66]

I have exactly the same problem with my tdi90, the problem started just how u have described but mine has got worse to the point it's at now which is in perminant limp mode. First you need to check if your car has the vnt turbo, not all tdi90s do. Check the engine code to see if it does, mines the ALH and does have vnt, for others just search this forum. I'm going to start taking my car apart tomorrow to start the cleaning process, the inlet, egr and the turbo. I'll report back, with pics if I can, on how I get on. From what I've read it's not the hardest job to do, just time consuming to make sure it's done right and carefully.

There's a nice guide to the vnt and why it sticks with lots of pics floating around here, can't remember the link but if u search related sticky vnt threads you'll find it

 

[Chris_Hardy]

Thank you for your reply, but am a little worried about the idea of permanent limp mode!
I have had a quick look and from your thread found out that I need to check the data sheet on the service book and there is the ALH in big bold letters.
So i have a VNT turbo and would this sticky VNT vanes seem to be the problem compared to various sensors failing?
I will have a look for sticky vnt threads and find out as much as possible.
But would be very interested in how you get on, would be good to see some pictures to compare, as my father in law and I looked at the EGR value yesterday and this seemed to be working fine.
Thank you for your help!

 

[S3 AKR]

I'm fairly sure the EGR wouldn't be the cause as many people block them off, remove them or restrict them. I think I'm right on saying that an EGR opens on full throttle so even if it were permanently open you wouldn't lose that much pressure as to feel as in limp mode.
If you have access to VAG-COM then there is a VNT exercise routine that can be run from there - it might help I s'pose (probably a long shot but if it did, it would save you some time!).

 

[Muttley]

We need to know what engine we are talking about here, ALH (which does have a VNT turbo), or AGR, AHU, 1Z or something older (which do not). What age is the car?

How many miles has it done?

Ar what speed range does the power loss strike? Is it during cruise or when overtaking (which puts additional load on the engine and will open the EGR valve, as well as opening the turbo vanes, or trying to)

Is it starting to happen at lower speeds, i.e. is the limp mode threshold creeping down?

On a VNT turbo, the no.1 cause is sticking vanes. They stick partly open, and when the engine calls for more power, the extra gas volume causes the turbo to overspeed, giving too much charge pressure and triggering limp mode.

On a non-VNT turbo system, the EGR valve gets clogged up after a while
(75K miles in my case, with a Mk 2 Ibiza TDI 90, AHU engine)
with the sticky sludge that also blocks the inlet manifold
(a product of the oily crankcase breather fumes meeting the hot sooty exhaust from the EGR)
and sticks partly open. The EGR valve mainly opens during periods of high power demand at medium revs, then closes as revs rise to be shut at full throttle. If it sticks open, too much exhaust pressure gets through, adding to the turbo boost to give overpressure and again limp mode.

 

[Chris_Hardy]

Thank you for the replies so far, I did look on the services book this morning, I added that its a ALH engine which I now understand has the vane VNT Turbo, its a 2001, Y reg car.

It has done a 117k when recently purchased.

It can be trigger at 'lower' speed if revved too high up hills for example but you have to be pushing fairly hard, but the main problem is motorway driving. When cursing ( over taking lorries) in the middle lane put your foot down to pull into the fast lane 75 plus and the power drops a couple '000 rpm, you can cruise at the current speed but no faster, if you slow down then it takes a while to get back to 75, there is even a loss in power when getting off the motorway, stopping and pulling on to the roundabout it feels like an old transit van (nothing against them but have driven a couple), feels like the turbo has been cut off, high engine noise and no acceleration ( which I understand is limp mode).

It happens between 70 - 80 band which is the overtaking band so i have lost all confidence to pull out now until there is a massive gap.

I must say i think its feels like it has been driven in town for too long as we both drive a lot of motorway journeys at weekends and gunning it up and down the motorway I think it has been getting better maybe I am more aware of the problem therefore I would say to your reply that its getting better slightly, the point is creeping up rather than down. But it could be as I have changed my driving style as I know the limits of the speed now so don’t accelerate quickly but work my way to the limit, but this does happen on every motorway journey still.

 

[S3 AKR]

It needs sorting though as you should be able to overtake safely without power loss, and that aint it!!

 

[funkmonkey66]

Quick update, taken the egr off my car so far and the inside is coated in about 5mm worth of crap, and so is the intake! the air filter also had a small slit in the outer seal and the air box was half full of rubbish (leaves etc). cant post up pics yet as i havent posted enough to link to my photobucket page.

 

[Chris_Hardy]

Thank you for the update, i hope you get that all cleaned up and solves your problem, keep us posted! I have checked the air filter and the hoses on the inlet (nearside inlet air filter and hoses) this seems very clean and the air filter was almost new. I checked this when i first got the car.

There is one other thing i could try the 10 k boost product, if i could get some of this in the system would this help? Clean out some of the soot etc in the inlet, egr, valves and turbo?

Failing that i would have to get it on some ramps and have a look at the diy cleaning or even innotec turbo cleaning what are your thoughts on this?

,,,,, failing this it will be off to the garage ( £££££ )

Any thoughts on the cleaning products 10 k Boost and DIY options Innotec cleaner ??? Thank you for your help so far, would like to hear everyones thought and advice on the above.

 

[funkmonkey66]

I considered the innotec route and i would guess that as your car isnt as bad as mine yet it may be a good option for your situation, although i think this is generally considered a short term fix (i could be wrong). The best bet would still be to have the turbo removed and the VNT mechanism cleaned properly. Personally after what i have seen today its definatly worth cleaning everything to do with the air intake and the turbo mechanism, theres no point just cleaning one part for it to get clogged up again by the other parts that were neglected. I would also strongly recommend doing the CCV modification to stop the nasty oily gasses getting sent back through the intake system, i know this is there to make the engines 'greener' but the downside is that the engine is being suffocated. I would estimate that my intake manifold as about 5-6 mm narrower than it should be due to the amount of crap lining the insides, and the air that is managing to enter the combustion chambers will be flowing far from smoothly.

If you are fairly handy with a set of spanners i would:
1- CCV modification
2- Innotec the turbo
3- Take off and clean the EGR and Intake
4- Combine all this with a service and chuck some fuel treatment in the tank
5- Make sure your MAF is in good working order aswell.

Im lucky as i can afford for the car to be off the road so have the time to remove the turbo instead of innotec'ing it, but i would of thought the above could be done over a weekend if you have the tools and the time.

My post count is now creeping up so hopefully i can link some pictures soon.

 

[S3 AKR]

My post count is now creeping up so hopefully i can link some pictures soon.

Go say Hi to loads of newbies in the "hello" section or whatever its called!

 

[funkmonkey66]

Go say Hi to loads of newbies in the "hello" section or whatever its called!

Haha good call!!!

More pics to come once ive uploaded them but this one gives an idea of the state of the insides of my intake system (pic quality isnt great, off my iphone)

 

[sssstew]

thats not too bad, ive seen alot worse. But a good clean up, then strip and clean the turbo.

 

[MarkWales]

going to need to do this to the other halfs golf tdi90 soon 137k and going into limp mode everytime power is called on past 2500 rpm

 

[MarkWales]

drove the car quite hard this morning and to my suprise did not go into limp mode - instead blew the hose from the fmic off going to try and reconnect

edit all parts there luckily and from looks of the car has happened before because previous owner has cut the inner arch liner to expose the hose and fmic

think this proves the stuck vanes as car is overboosting

 

[MarkWales]

update

refitted the hose

disconnected the plug from the black vacuum controller (N18) - NO WARNING LIGHT

test drove very hard boosting fine all the way to 4500 rpm



NO LIMP MODE