Hi Folks,

As some of you may know, I have an 02 plate Fabia 1.9 Tdi which I've had a month or so. I've been driving it very gently so far (gentle acceleration and aiming for 60-65 on the motorways) and it's been absolutely fine. But this weekend on a 500-mile round trip to Wales I decided to drive it a bit more 'normally' (80-85mph, boot full of stuff). It now seems very sluggish, particularly at speeds above 70, and on hills.

I tried to over take a lorry on the A69, and had to pull back in - seemingly no power. In 100 miles of motorway, I didn't manage to get above 85 once, despite pedal to the metal, and found myself losing speed on slight inclines. Also, backing off the throttle even for a second (eg when somebody pulls out) causes me to lose momentum which is almost impossible to get back.

I did manage to get 100mph fairly easily on a quiet section of duel carriageway this evening, but it still feels sluggish. And ten minutes later, I was stuck at 85 again, with no prospect of speeding up. I also noticed a couple of 'blips' while accelerating (eg: I was accelerating through 60 in 4th gear today, when I heard a change in engine noise and the rate of acceleration slowed dramatically).

There's no check engine light on. No black smoke. After a look on here, I disconnected the MAF. Drive it for 15 minutes and no change.

Any ideas? If I can get hold of somebody with a VCDS cable, will that be any use even if there's no check engine light? I have an appointment with the local Skoda dealer, but it's not till next week, and I'd rather solve it before then, and cheaper!

Any other ideas? Turbo? ECU? I thought maybe clutch slipping, but I would expect erratic/ high revs. For reference, I'm doing about 75mph at 2500 revs in 5th.

Also, when I took it for a 'free health check' at ATS, the only thing they mentioned was a minor leak in the back box. It was described as 'fair' condition. Is it worth looking into that? Could it cause such a dramatic (and erratic) performance loss?

Thanks in advance.

It wont be the back box.. could be a boost/ vacuum pipe has a slight pin hole in it.. when driving normally it doesnt get hot enough to expand + leak.. but when hot (ie when your booting it) the pipes expand and the pin hole becomes a leak.. only intermittent though while ur booting it.. when the pipe cools down the pinhole seals itself..

Or it could be the turbo vanes sticking.. this is a fairly common problem that can be cured without having to replace the turbo.. a DIY job if your fairly capable or a turbo specialist can sort it..

When u boot it + there is no power.. turn the engine off + back on while driving on the motorway (u will not need to use the starter just release the clutch).. u might find the power returns ..

Good luck

Edited 29 April, 201313 yr by mattvrestate

Thanks. I'll try switching the engine off/ on and see what the result is.

These boost pipes. Are they the rubber hoses going into the unit by the brake fluid reservoir? I had a quick look at those yesterday to check they were all connected. The one going to the air filter seems a little loose (just slides right off and on without much persuasion). The others go to all sorts of weird and wonderful places but seem to be OK so far.

What is that unit anyway?

Turbo vanes. Is that something that would turn up on a diagnostic machine?

Ta.

The unit is a vacuum control box.. and the small pipes go off down the back of the engine.. one goes to the turbo actuator + one goes to the egr valve/ asv.

The best way of checking for small leaks is by using a mity vac.. creating a vacuum in the pipes + seeing if they hold the vacuum.

It would be worth seeing if there were any faults on a diag machine like vag-com or a dealer VAS machine but the sticking vanes and/ or vac pipes wouldnt show up as a fault unless there was a major leak then an underboost fault might be stored.

Well, your speed/1000rpm is about right (you did mean 60mph @ 2_000rpm? ).

The turbo is behind the engine and the intercooler in the front of the RHF wing, so the pipes run along the cylinder head, in front of/above the auxilliary drive belt, and then dive to the arch.

You could try putting a catch tray under the joint in the arch, and disconnecting the lower pipe. This may drain oil out of the intercooler, which causes you mass flow problems without causing boost pressure problems.

Just taken it into Volksentre.

They couldn't find the problem on a test drive. (Typically, it was driving like a dream at the time.) But the diagnostics showed a couple of codes:

17964 Charge pressure control

17664 Coolant temperature sensor

I'm guessing the coolant problem is unrelated, but I'll get that changed anyway. Seems cheap enough.

But the 17964 code seems the culprit. Before I go messing around unplugging the hoses, is there a diagram / description somewhere of what should be connected to where? Is there one of the hoses which I should be paying particular attention to?

Thanks again.