Stock family car without any modifications/duning.
!!! Main cause of your problems is YOU !!!
There are car users suffering from illusion of saving money and Mother Nature.
It is easy to spot them:
- using TDi for short trips
- driving carefully because speed is main cause of accidents right. Everybody knows that. And if you drive 30 km/h on the highway, it saves countless lives…except yours, and that poor fucker who crashed into your carefully driven car.
- using the cheapest fuels from questionable petrol stations
- driving at idle engine speeds – nothing kills engine quicker than driving 50 km/h in 6th gear with engine around idle speed. While it may save the environment temporary, it damages the engine, and your pocket.
!!! YOU !!!
Poor man always pays twice.
Poor fuels from questionable petrol stations – give yourself a favour, and stop “saving” money.
If your EGR valve looks like the one in above by image, the same crap is in your turbocharger. That is how normal, relatively clean, engine looks like (image below)
In those rare occasions where you did everything right, and your beloved car is slowly dying by wear/tear.
Diagnosing causes 1-2 is self-explanatory, and need no elaboration. Stock car, with proper maintenance, intelligent car seat, lasts at least 200’000 km.
Simplest test for sticky vanes needs no garage, coveralls or getting dirty. Find a long straight, abandoned road where you cause no accident, and carry the following test:
- reach enough speed where you can drive steadily in 3rd gear.
- check out if there is no car on the road in front or behind you.
- slightly lift-off accelerator, and let engine slowly drop to around 1’500 rpm.
- floor it/pedal to the metal – your engine will try to desperately accelerate
- up to 1’700 rpm, your engine struggles and seems to be lazy…doing seemingly nothing. Engines 1.9l may kick in at around 1’800 rpm, smaller engines 1.4l even at 2’000 rpm.
- From 1’700 rpm, you must feel noticeable acceleration once turbocharger has enough exhaust gases, and compressor starts to provide more air for engine.
- if your engine keeps slowly, lazily increase speed…there is something wrong.
If you are car hacker with OBD diagnostic, you can log requested vs actual boost. Any larger discrepancy than usual -400/+200mbar suggests turbocharger issues.
If Test 1 failed, you have to find out what may be the problem. The first step is turbine control via actuator.
Modern turbochargers have servo controlled vanes, and you do not need to worry about this test.
In old TDi cars, turbine vanes are controlled mechanically by vacuum actuator.
You have to find out where turbocharger actuator, N75 and vacuum pump are located.
Some cars have an actuator from the bottom. You need a mirror on stick and torch to see for any signs of rust. You can usually move the rod with a hand with ignition switched off. There must be free movement.
If there is rust, it may be stuck. If there is no movement, it is completely rusted, or the screw may be loose and simple readjustment may do the trick.
Next step is to find out if vacuum system works as suppose to. Whether N75 valve is faulty or vacuum hoses are worn/leaking air.
Remove the inlet vacuum hose from N75, and check out if you even have vacuum in from the vacuum pump.
To make sure, just buy rubber hose, and replace all vacuum hoses…it cost few bucks, and return on investment is instant…you waste at least an hour by checking out vacuum hoses for leaks. It takes less time just to replace them for new ones 😉
Remove vacuum hose from actuator, and check if you have vacuum out from N75 valve.
N75 valve may be tested with OBD diagnostic tools such as VCDS. You can switch the valve on/off via OBD tools. I am guessing it may be possible to test without OBD tools and just with extra hands.
Removing vacuum hose from turbo actuator, while your friend is revving, the engine may switch on N75 valve.
If Test 2 has weird results such as restricted movement of actuator rod. You have to estimate whether is worthy to carry any quick fix kludges or replace turbocharger.
Apart from lack of boost or inconsistent boost. A simple test for condition of turbocharger is to check engine oil leaks in intake manifold.
Find the lowest part of intake manifold – usually between IC and throttle body – and remove air intake manifold.
If there is lots of oil, and you must also fill up engine oil. The scroll bearing inside the turbocharger is damaged.
Properly maintained turbocharger last 200 – 300’000 km. Short trips, poor maintenance = turbo dead within 50’000 km or even less.
Czech taxi drivers used to do 1’000’000 km on legendary 1.9 TDi 74kW…turbocharger leaked oil slightly, but still boosting without issues.
There is not much you can do, but some quick/temporary fixes may help your beloved car. Assuming you finally understand issues with car seat.
Quick fix #1
Burn the crap out – if you are lucky, and there are just few carbon deposits or some crap from poor quality fuels…driving flat out in mountains with constant 800 °C EGT may burn deposits off from turbocharger.
Quick fix #2
Replace N75 and all vacuum hoses.
Quick fix #3
The ghost in machine, nothing makes sense ever since of electronic management and OBD was invented. I had many issues with boost, EGR, and guess what…it was faulty MAF, and OBD forget to tell me.
Car mechanics wanted to swap all parts in engine…always last place you look 😉
If you have own garage, no life, and lots of spare time…you can try to clean your dying turbocharger.
Of course, if your turbo has got 300’000 km and 20 years – it is just a waste of time considering how much costs officially refurbished Garrett turbochargers (mine costed me <400€).
It took me about 12 hours, and lots of swear words, to replace the turbocharger. With average salary 20€/hour, it is 240€ gone. What if your turbo is already dead, and you will have to replace it anyway…another 12 hours and 480€ gone/wasted.
Remove the turbocharger from the engine, dismantle it, and clean all you can. There will always be some remains, once you have cleaned the sticky soot mixed with oil, carbon deposits.
Use petrol, pour it inside the turbine, and light that shit up. Watch the show, it burns remaining crap out. Of course, you have to remove all flammable parts of turbocharger.
Housing, and vanes can handle easily 800 °C…no worries.
Assemble everything up, adjust actuator rod so that vanes move as suppose to, and hope your turbocharger is not dead, and you didn’t waste a whole weekend by unfixable.
You just postponed the inevitable…one day, that old turbo die anyway.
There are times when it is easier just tu buy a new/refurbished turbocharger…assuming you have pinpointed the exact cause of your car issues.