I have a 2002 110 TDi Octavia mk1 L&K which has done 144k miles.

Problems:

+ If I accelerate slowly through the rev range, between 1500-2000 rpm the boost will turn on and off strongly, making the car feel like it is going backwards a few feet.

+ If I accerlate more quickly, the on/off feeling is still there but it goes away - it also goes away if I lift off the throttle (but makes a scraping/hollow metal sound when I do).

+ It does this in all gears but most notable in gears 2,3,4.

+ It will frequently go into limp mode at 2000rpm if cold, or sometimes up nearer 3000rpm if warm (driven for say 30 minutes previously).

+ The turbo always starts off working, it has always been operational, it just goes into limp mode if I push it too much above 2000rpm.

+ These above issues are worse going up hills.

+ The ASR light has started coming on too, often at the same time as this jerking on/off activity.

+ I only have Android Torque app with a bluetooth ELM32 code reader. It reports no logged fault codes in the ECU.

+ Torque shows me that my boost in PSI is going up to 22 just before it goes into limp mode.

+ Slightly subjective but the turbo seems to spool up better on very wet / damp days. Dry days it jerks much more.

Other info:

+ The MAF and CTS have not been changed as far as I am aware (nor any turbo hoses/pipes have been changed).

+ I know that the EGR and inlet manifold are very dirty. I often get the EGR valve stuck shut after short journeys and need to manually push the solenoid rod to allow the car to restart.

+ The fuel and air filter have recently been changed.

Given the behaviour above, what is the most likely cause for the turbo to turn off so frequently? (I can get it to turn off on almost every journey)

Any help very very much appreciated

either a vacuum leak on the small pipework or sticky vanes in the turbo (or both) 23psi and 3000rpm is the cutoff point for limp mode due to overboost

either a vacuum leak on the small pipework or sticky vanes in the turbo (or both) 23psi and 3000rpm is the cutoff point for limp mode due to overboost

(1) Whats the best way to find the leak for the hoses? Does anyone have a picture of the hoses (or can describe where to look for them) so that I can check if they are split / disconnected etc.

(2) With the sticky vanes, I need to remove the turbo to clean it obviously. I think you can get the turbo out from above the engine bay IF you remove the EGR/anti shudder valve and the inlet manifold? Is this correct?

As I need to clean both those items it makes sense to remove and clean the turbo at the same time, as even if it doesn't need cleaned now (which I find unlikely!) then it will soon.

(3) Could a faulty MAF or CTS be causing these issues or is it only really broken hose and/or sticky vanes?

(4) Also, what is the reason that the turbo playing up would make the ASR warning light come on? What does this normally indicate? I think I read on here somewhere that MAF issues can cause that light to come on for some weird reason, is that correct?

Many thanks!

Edited 31 October, 201114 yr by Gunswick