Hi all

After successfully getting my wife's '01 octy flying, I recently bought a '03 Octavia 1.9TDI Ambiente everthing has been going well but recently I have found the car a little lacking in power on acceleration and it just isn't as nippy as my wife's which has the exact same engine. I got a diagnostic done on it this afternoon and the only error to pop was the one below:

17965/P1557/005463 - Charge Pressure Control: Positive Deviation

I have done a bit of digging on the internet and from what I can find is it could either be sticky veins in the turbo or a faulty MAF. Would this be a correct diagnosis or could anyone point me in the correct direction of troubleshooting this?

Thanks in advance,

Edited 10 February, 201313 yr by claytonie

Mr muscle mate, search for it on the forum, works wonders

Mr muscle mate, search for it on the forum, works wonders

What he said - there is a guide by Lofty in the General Guides Forum.

Mr muscle mate, search for it on the forum, works wonders

I thought as much was reading through Lofty's guide already but wanted to make sure it would be the same for the 90 engine as all the posts I saw referred to the 110TDI

his was a 90 bhp alh same as mines and yours ?, 110 is the same so long as its not a pd

The earlier 90bhp engines don't have the variable vane turbo and so can't suffer from the sticky vanes problem but as you have a later one with the same sort of VNT turbo then it's a good chance that this is the source of the problem.

It tends to arise when the car is driven too sedately, they like a good blast every now and again to help keeps things moving.

his was a 90 bhp alh same as mines and yours ?, 110 is the same so long as its not a pd

LOL I think I had read so many threads that somewhere I got it stuck in my head that it was 110 Hopefully tomorrow is a dry day and I can get a good look at what needs to done. While I'm doing the Mr muscle treatment is there anything else I should be doing like cleaning the EGR valve?

Well you may aswell clean it between going back and forth from the turbo so why not, get a tin of brake cleaner helps with cleaning the egr

^^^ what he said ^^^

That said Mr Muscle isn't a total cure. I have cleaned mine three times (1st time I took it off, and then 2 lots of Mr Muscle), but it is getting sticky again :-( I normally give the car a bit of a stick, but most of the time is is going about 2000rpm/55-60mph on the country A roads to work, I don't often have to change gear often either.

Mr Muscle will presumably remove any carbon deposits but if there is any rust then it won't shift it. I remember a few posts from someone on here who had stripped down quite a few turbos where the issue was corrosion which was limiting the movement of the vanes.

Well it's £7 of cleaning products to see if it makes a difference for the guy, i agree with the corrosion part, but hes not gona know unless he takes the manifold off and strips it, but as mbames said it takes a few goes, but first time you will notice the difference.

Mr Muscle will presumably remove any carbon deposits but if there is any rust then it won't shift it. I remember a few posts from someone on here who had stripped down quite a few turbos where the issue was corrosion which was limiting the movement of the vanes.

Hopefully the mr muscle does the trick! Would it be normal that I never get limp mode? Car goes fine other than just a bit sluggish on acceleration. I just took a spin to the shops and I can hear the turbo whistle but it just doesn't seem to give it as much boost as it does in my wife's car.

Your vanes may be sticking in the 'open' position, resulting in an underboost rather than an overboost which normally causes the limp mode.

Edited 10 February, 201313 yr by Ben90

An other thing it could be is the turbo actuator not fully working, as this is currently a problem on mines, the turbo wont open fully

Ok guys so I did the Mr Muscle this weekend, I tested the actuator before I started and I was able to move it fine but figured since I got everything I would give it a go anyway. Unfortunately after doing it there is still no change :( Would the next thing to try be replacing the MAF? If I disconnect the MAF the car loses all power completely and seems to go into limp mode is this normal?

My fuel consumption also seems to be out the trip computer reports me averaging 63.3MPG but real world doing a brim to brim fill logging it on Fuelly shows im doing 48.9MPG which is a huge discrepancy.

Edited 24 February, 201313 yr by claytonie

If it runs better with the MAF unplugged (the ECU resorts to using 'best guess' figures) then the MAF will be faulty. If it runs the same eitherway then it's not the MAF either.

You may have a boostleak, that or the N75 valve is faulty.

If it runs better with the MAF unplugged (the ECU resorts to using 'best guess' figures) then the MAF will be faulty. If it runs the same eitherway then it's not the MAF either.

You may have a boostleak, that or the N75 valve is faulty.

Its way worse with the MAF unplugged! While I had engine cover off I checked all the vacuum lines and couldn't find any loose or perished ones.

What causes the huge discrepancy between trip computer fuel consumption and real life?

Edited 24 February, 201313 yr by claytonie