Chiptuned Golf 6 CBDC 2.0TDI smokes badly for periods

[seb15243]

Hi,
My 2009 Golf 6 CBDC 2.0 CR TDI is doing some weird stuff from time to time:

I`ve only had the car for a week and the previous owner had it tuned with a MTM tuning software + electronically "disabled" the EGR valve without blanking it (dunno if thats a great idea)
The day I bought it I had the oil and filter replaced. What worried me though, was that I drained 7 liters off the engine (as far as I know the engine takes 5L)
So I called the previous owner, he refused to have put in 7L in the engine. The old oil was normally colored, wasnt too thin and didn`t smell of diesel so water and diesel ingress cant have happened..
Anyways.. I changed the filter and filled up just over 5L 5W30 fully synthetic oil and checked the dipstick which was fine before doing anything else.

Sometimes while driving normally (1800-2000 rpm) the exhaust start pouring out a blueish unburnt dieselsmelly smoke and it would keep doing it at any engine speeds.
The next day, its completely gone. Even at hard acceleration, smoke is gone.
Offcourse, I thought it would be the car doing a DPF regeneration but it seems to happen over and over again.. No warning lights, no trouble codes on the system. Could this be related to the EGR being disabled? The previous owner told me all the crap that is supposed to go in the EGR, would now go straight out the exhaust instead of back into the intake and that could cause the smoke.
The engine also has quite a bit of turbo noise, might be a leak somewhere but the sound worries me.. I dont think the noise is related to the smoke issue as its periodic and the turbo noise isnt.. The car has only done 120k kms, the turbo should last longer than that, right?
Would love some response here as this got me quite worried

[Gazwould]

The weird bit is the inconsistentcy.

EGR is the strangest device ever put on a car engine , it achieves one positive act to several disadvantages and that's a fail in my book .

EGR disabled will only aid better more complete combustion of diesel fuel molecules resulting in less unburnt - soot , as well as better turbo spool from undiverted exhaust gasses and a whole lot more...

[philipharmes]

If the EGR has been disabled, blank it off, then you can be sure it isn't leaking & affecting combustion.
It's a 10 minute job to blank it where the EGR pipe bolts to the front of the block with a suitable plate.

The raised oil level & smoke is almost certainly coming from unburnt diesel from multiple regens.

Keep a close eye on the oil level.

Has it still got it's DPF or has that been gutted ?

[seb15243]

The EGR probably needs to be blanked yeah, so I will get that done asap.
The DPF is still there. The previous owner told me he had a DPF/exhaust icon on the dashboard (he used the car for shorter trips) and a long drive to burn out the soot had solved the issue. No problem ever since.

The oil level thing really had me worried. The previous owner was very confident that he never overfilled the engine. I remember pulling the dipstick in the rain before i bought the car and the level was fine, although the engine had just ran at that point. Then I drove the car home (3.5hours of highway speeds) and when I checked the dipstick at home, the oil level was too high. As I said earlier, the oil didnt stink of diesel fuel and it wasnt thinner than on other similar engines ive drained in the past.

I will keep a very close eye on the dipstick, in fact I will check it every day instead of just a few times a week.

I havent been out with the car today but will do later. I shall keep you updated

[seb15243]

So I just went for a drive. Checked dipstick before starting the engine. Dipstick was good. No smoke at all and the engine got up to operating temp so if it «wanted» to start a DPF regen, it could. But it didnt seem like it did. The turbo noise is still there. Should you be able to even hear the turbo from inside the car at low revs? All the other CR 2.0 TDI’ s ive driven I havent heard any turbo sound at all. It could have to do with less soundproofing in the golf than for example in a Tiguan but i test drove a few other Golf’s before I bought this one and none of them had that much turbo noise as this one does.

[Crasher]

Really you should never hear the turbo, you may need to force the regen using a diagnostic system and reading the loading figures would be a good idea.

[seb15243]

Yeah thats a great idea. Ive got a somewhat decent diagnostic tool so I’ll try to force a regen.

It sounds like the turbo is knackered (or about to be) then.. Typical my luck... weird if it to goes as early as 120.000kms but at the same time the car is old... Replacement turbo new or maybe a refurbished one ?

[Crasher]

Unless seriously damaged, we always have the original unit rebuilt.

[philipharmes]

" Then I drove the car home (3.5hours of highway speeds) and when I checked the dipstick at home, the oil level was too high. "

That raised oil has to come either from coolant ( which you would have noticed ) or diesel ( most likely from excessive regens ).

Although you say the oil looks ok, the diluted oil will affect the turbo lubrication.

You need to find the cause of the excessive regens before replacing the turbo, or the new one will go the same way.

Perhaps get the VAGDPF app so you can keep a close eye on the regens.

[seb15243]

After driving a few more days now, the oil level does not seem to rise at all. Im quite confident the high oil level must have been from the previous owner overfilling when servicing the engine and that I didnt check it properly when buying the car (The previous owner kept the car outside and it was cold, raining and getting slightly dark and the engine had literally just ran when i checked the oil) I should have seen it anyway...
He told me he had changed the oil and filter 3000kms ago but I always like to know what oil (and in this case how much of it) I have in my engine at all times....
The car still smokes at totally random times but it seems to start smoking before it gets up to operaring temperature and it might dissapear after driving for an hour. Other days it doesnt smoke at all.. Im still supspecting this to be DPF regens so will have to check the soot level in the DPF etc.
On the Tiguan with a CBAB engine (I believe) we had it tuned and also electronically disabled the EGR valve but never had any smoke with one exception and that was clearly a DPF regen but it never did it over and over again..