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Throwing this out there before I dig deeper... anyone managed to resolve similar issues?
My 115hp TDi is having some limp mode issues.
First a few comments about what is strange in comparison with my other TDi:
Especially when engine is cold in lower gears, there is quite a loud turbo cavitation sound when changing up.. (absent in my other TDi)
Cycling the VNT actuator, the turbo spools up quite loudly... is this normal?
Goes into limp mode at ~3500 rpm in 3rd.
The actual maximum pressure does not seemed to be measured by VAG-COM.(maybe faulty boost sensor?!)
Do you have some advice for me after looking at the video?
Last edited by retrovan on Sun Mar 02, 2014 11:04 pm, edited 1 time in total.
1952 Split Beetle 1835cc
1968 Fastback 2Lt.type4
1972 Low Light Bay Panel Van 2Lt type 4
1975 Fleetline Panel Van 1914cc
2020 MeFusco Beetle Truck 2Lt type 4
1972 FT Hahn SP 1776 cc
eben wrote:Been there already Thanks
I've got two main suspects:
1. Sticking VNT vanes because of sooting...
2. Faulty boost sensor...
Hi Eben , plugging in a diagnostic tool would confirm which one is the culpret , they are both common faults and its a 50-50 toss-up without a fault code.
Our local cars suffer from the vanes getting clogged but i suspect you guys have a better diesel over there (with emmision laws being enforced) but the fact that there is also a wine from the turbo suggest you problem lies within... boost sensor would not cause a turbo whine.
good luck and keep us updated
My biggest fear is that my wife sells my cars for what i told her they cost !!
Hi Eben
As you might know , that means the car is overboosting , the std management has pre set parameters for boost press at certain rpm ranges whats happening now the vanes are stuck or cant move to the correct position thus creating the overboost fault .I see a turbo removal in your future hopefully the nuts and studs on the turbo are not to rusted/heat treated that you get them out without any breaking good luck. You can take out the boost sensor usually they are mounted on the intercoolers and give it a clean with some carb cleaner but my money is on the turbo being the culprit.You might want to look at the turbo oil feed and return pipes while you are at it.
My biggest fear is that my wife sells my cars for what i told her they cost !!
This is interesting , they claim you can clean the vanes without having to remove turbo - depends on what Tdi you have , not much space to work with in Polo
I have removed my turbo 5x in last 3 weeks and can do it in 2 hours flat
Ohh yeah word to the wise DO NOT RECONDITION just buy a new one if damaged , cleaning is OK
This is what it's like without load.... This can't be right... doesn't happen with my octavia... The turbo should not be spooling like this without load.
Must be sticking vanes..
Fixed it with oven cleaner...
Lets see how long it lasts..
Before and after graphs:
Yellow = Actual Boost
Green = ECU requested boost
Red = Engine Speed
Grey = Boost controller duty cycle.
Overboost.jpg
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stick some flexible tube in there carefully so it goes to the HOT side
using a head with a tube (like you get for oils spray), spray foaming oven cleaner(Mr Muscle supposedly works best) into the pipe while clamping the top to make sure it goes down the tube.
keep going until the foam just comes out or the EGR hole (it should not go up the exhaust manifold to the head!)
Let is sit for about 5 minutes
Using some pliers, carefully start manually moving the VNT actuator. YOu will find that is starts moving with less resistance.
Let it sit a bit more
WOrk the actuator repeatedly about every 15mins until you feel that it is moving freely and through the whole range or movement.
Replace your EGR pipe
Start the engine and rev it to min 3000 for about 30sec - 1 min, making sure your exhaust points to somewhere that you don't mind getting dirty.
Check everything runs OK and go for a nice brisk drive using WOT in 3rd gear upwards to see if your engine is not going into limp mode anymore...
PS this is assuming your issue is sticky/dirty VNT vanes... this will not fix other issues with your turbo ie. seals, actuator leaking etc.
Thanks
