Turbo overboost problem 1.9 tdi asv

[janjazmaj]

Hi guys i have a big problem lately.
I always intermittently had problems with vnt on my car because 90% of my driving is city reaching speeds up to 20kmh
It would go into safe mode when i go above 3.5k rpm and limit the power until i restart the engine.
Lately it developed a new problem where it under full throttle it does not activate safe mode, but it starts jerking and i can hear a wierd chirping sound from turbo every time it jerks.
I logged the turbo requested/actual pressure using vcds, and on vcds graph, the acual boost goes through the top of chart waaay above the requested boost and the whole car feels slugish as hell.
At 3k rpm requested boost is 1866 mbar and actual pressure is 2427 mbar.
Am i looking at the chart wrong or is something wrong big time?
Thanks in advance guys.

 

[iammooks]

There are some things in what you said that I recognise from the issues with my car (PD150). I had some issues that started with being occasionally down on power and at times when the engine was cold, being unable to get it past 3,500rpm. I pretty much sorted that by doing the Mr Muscle treatment where you take the exhaust side of the turbo off and spray oven cleaner in and work the turbo actuator.

What turned out to be causing the biggest problem was a boost leak at the intercooler pipe, so maybe check those too - the lugs do wear on them, and if they're the originals them they'll be pretty old by now. I think that can cause overboost because the boost leak means less pressure, so the turbo tries to create more that also escapes.

The chirp I narrowed down to it probably being the turbo actuator. If I accelerated hard in first or second, I'd hear a chirp probably a second or two after lifting off the throttle. I sprayed some penetrating fluid around the actuator and worked it a bit, and haven't heard it since, but I also changed the vacuum line to the actuator as well, so it could have been a leak there. Mine sounded like the noise a dodgy solenoid makes. If your turbo vanes are gunked up then it could well be that.

So yes, check the boost pipes for leaks - they'll be pretty obvious - and think about cleaning the turbo. It gives you a chance to check for play and just generally get a look at it.

I wasn't getting any codes or lights at all when this was happening, which made it a complete pain to track down the issue, but these are cheap fixes before you really start tearing things apart...


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[janjazmaj]

Thanks for the quick response buddy will go to the local workshop anyway as its almost due for a yearly service, so i guess will be adding turbo cleaning to the fix list

 

[Rich.T]

iammooks = diesel guru

 

[janjazmaj]

Well i found a quick and simple solution to overboosting issue.
When i got on the highway first run the car could barely pass 130km/h and turned on limp home mode.
After gradualy blasting the living crap out of it at 4k rpm for 20 minutes everything went back to normal, now it pulls like a charm it even turns on T\C in second gear
If anyone has the same problem this could be the fix and adding some turbo cleaner additive could make it even better

 

[Nam-uk]

Well i found a quick and simple solution to overboosting issue.
When i got on the highway first run the car could barely pass 130km/h and turned on limp home mode.
After gradualy blasting the living crap out of it at 4k rpm for 20 minutes everything went back to normal, now it pulls like a charm it even turns on T\C in second gear
If anyone has the same problem this could be the fix and adding some turbo cleaner additive could make it even better

nothing beats a good heavy right foot and getting that turbo upto temp too keep everything from gunking up, short journeys are the worst but sometimes you cant help it, just plan in a good run now and again in your daily life, that goes any vehicle

 

[smutts]

Chasing Teslas up Haldon Hill usually keeps mine in good fettle.
Haldon Hill is why the south end of the M5 stops where it does.
Also why when it snows here, you just give up.