Ibiza Cupra 1.9 - Limp Mode with no CEL = Turbo Vanes Sticking?

[Marlowe]

Hey guys (and gals). I'm a long time lurker that's always found the resources here great, but never had anything to post really, until now.

Myself and the missus bought an absolutely stock 2005 1.9 pdi Cupra last year (she has a 90 mile commute every day and I'd always liked the MK4 Cupra so it was a no brainer). The car's had a few issues along the way (mainly because it seems a bit neglected by its previous owner in terms of cheaping out on maintenance), which I've always managed to sort.

The one recurring issue though is that the car has an intermittent limp mode since the time of first owning. It always happens when on the motorway at 80mph+ and never generates a CEL. Pulling into the hard shoulder and turning the engine off and on instantly restores power but this is obviously pretty dangerous for my partner and so I'm trying to sort.

So far I've tried:

-Replacing fuel filter in case of blockage (it was the original! ).
-Replacing air filter with a Pipercross Panel Filter
-2 x Full oil changes
-Replacing MAF
-Inspecting hoses for damage / leaks
-Using 3 seperate code readers - (own cheap chinese VAG reader, official SEAT diag tablet lent by a mate at SEAT, and a SNAP-ON from work - work in a college with a motor vehicle dept)
-Had the car inspected by Seat (mate), a local independent and technicians at work - all couldn't diagnose due to intermittent nature and no CEL / error codes logged.

I'm getting to the end of the tether with the car (this has been going on for 8 months now) but don't want / can't really afford to get rid of it. It seems more and more likely to be the variable vane sticking issue (previously owner was a girl who appears to have just driven the car around town) I'm debating having the turbo removed and cleaned out / possibly refurbed (the car has now done 105k and I think there's a slight blue in the exhaust smoke).

Before I go crazy with looking at sourcing a refurb turbo though could you guys maybe:

a) Tell me if it sounds like this is the right thing to do (I know N75 solenoid has been mentioned but unsure how to diagnose)
b) Recommend any specialists in South Yorkshire as the independents around here either don't seem to have a clue about or don't want to get involved in a turbo removal (not a criticism as I get it's not as profitable as changing some old dear's brake pads).

Cheers

Dan

 

[Lowe]

Mine (same age/car) does the same - but I get a cam shaft speed sensor fault code being logged. Might be worth a check though?

(hang on a minute - Marlowe and Dan from up north? You're not err, Dan Smith are you?)

 

[mgrays]

If it was a vane sticking.. then first lubricate externally with WD40 ... not nice but I now do it every oil filter change.. note it will smoke and you do have a possible fire risk while it smokes but IMHO a small one. Second is to give it some hard work outs i.e. Italian tune where you find a good long hill (2-3 miles at least) and really thrash it up there to the full rpms. This will blow out a lot of carbon and then I was working the vanes by being under heavy load and then full down on throttle, then off for 2 secs, then on. This will cause the vanes to move rapidly and may free them off. I thought I had sticking vanes and pulled and then stripped the turbo... getting the turbo out of the top is right pain! Took me best part of 2 days to remove and had to get a few new nuts and bolts (110k miles 05 car). The vanes were fine as I had been doing some Italian tuning instead of constant speed commutes or even worse town driving where engine fails to get up to temperature.

As the vanes are mechanical it might be true it gave a limp mode as it jammed ... but would still think it would throw a code as boost would not response as requested by ECU. My would/will go into limp if I lightly boot it up a fair hill.. if you floor it then all is OK.. it is the slow increase that would cause the vanes not to work right ( I think) and that with the chipped ECU would through an "implausible boost" code... but it would only show the dash engine light after about 3 faults in one trip... they then go away.
As for rebooting on the fly... just dip clutch and off with ignition, on with ignition and run start it by lifting the clutch. No doubt something I only do on a private road as potentially the steering lock comes in but been doing it for many decades on this private road.

 

[Mikb23]

I've had exactly the same issue with my 2003 TDI130 Sport. I was also getting cam shaft sensor faults in the ECU (but no engine warning light). It was happening maybe once or twice a week. Funny thing is I had a flat battery over Xmas which I replaced and ever since I've been 100% trouble free. Also my troublesome power steering light issue disappeared at the same time, never to be seen again. Not sure if the removal of the battery purged the ECU or if it was just coincidence but it's certainly done the job. I've gone over 4 weeks without any problems.

 

[uzi_cupra]

You really need to get vag com and go out on a run.
log measuring block 11 and in 4th put the foot down and at 2000rpm you should get 70-80% WOT, if you cannot achieve this (if you are under or above) then you're problem is fairly simple - an adjustment of the actuator will be the fix.
I would also suggest doing a vac test on all your vac lines to make sure none of them are split.

Before getting into that though, carry out a log and report the figures you find.