Could this be imminent turbo/engine failure? Black smoke, horrible iT

Hello everyone,

Let me start off with the history of my 03 ALH wagon. When I was viewing the car, I was never informed of the current limp mode condition that the previous owner was experiencing. I took the car for a test drive and it seemed to drive fine.

Paid for the car and it was fine for a few weeks until eventually limp mode became present.

When the car was in my possession, I have tested the MAF, installed a fairly new EGR from my old car and replaced all the vacuum lines. I've also re-checked my turbo piping to IC and verified my turbo doesn't have any side to side nor in/out play as I was curious.

Initially the limp mode would only show itself in the colder temps, spring/fall/winter. But this year, I can get it into limp mode anytime.

I've looked at the code and it's the overboost condition error that is generated.

The actuator is fairly new, installed by a TDI guru not long ago when it was in the PO's hands.

This spring, I've experienced two incidents that really make me worried about something going horribly wrong.

Both incidences were in the morning, a few short KM's from home on my way to work. The motor was on it's way or was fully warmed up...I can't recall.
Both incidents, I accelerated quickly in traffic to change lanes or enter a side road.

What happened was...I'd accelerate and instantly after moving I'd see a large cloud of smoke. Upon seeing this, both times I've let off the gas and made sure my car wasn't going to experience a runaway turbo. Both times I've noticed that the car will idle really bad and it seems to be in limp mode.

This early week, it happened again (the second time) so I quickly parked it and got out to record what I can.

Here is shortly after it happened.

https://www.youtube.com/watch?v=Lt4AgL1ESyY


Here is the car after I drove it for a short bit (100 feet or so)

https://www.youtube.com/watch?v=_4mCsQJNyfc


So I am not sure what to do here. I car drives/idles perfectly fine otherwise as long as I stay out of the hard acceleration/boost area.


Could my turbo be somehow clogging up and suffocating the motor?

Any ideas?

How old is the CAT Filter?

when you take off the oil cap, are you seeing a lot of blowby?

How many miles on this engine?

get yourself a harbor freight compression tester for diesels and see if your compression numbers are about the same all the way across.

its possible that the out of balance is from a small runaway event from buildup in your intercooler due to CCV and or turbo oil seals. the two cylinders in the middle would get more of this fluid than the outer ones and could be coated in unmetered oil causing the out of balance situation until its burnt off or compensated for by the engine computer.

start with the compression test and go from there.

I had been having the same sort of thing: get into the throttle and then a puff of black smoke and then would sort of "flat line" for a couple of seconds and run rough. What mine was, also happened to be over boost. Driver requests power, ECM throws out fuel to spool turbo, turbo doesn't spool, and ECM cuts fuel. Does any of this sound familiar?

Though it could be, I don't think this indicates imminent engine failure. It sounds like some engine controls are out of kilter.
[I know, not much help]

Growler said:

How old is the CAT Filter?
when you take off the oil cap, are you seeing a lot of blowby?
How many miles on this engine?
get yourself a harbor freight compression tester for diesels and see if your compression numbers are about the same all the way across.
its possible that the out of balance is from a small runaway event from buildup in your intercooler due to CCV and or turbo oil seals. the two cylinders in the middle would get more of this fluid than the outer ones and could be coated in unmetered oil causing the out of balance situation until its burnt off or compensated for by the engine computer.
start with the compression test and go from there.

Click to expand...

The CAT filter is just over a year old.
38x,xxx KM on the car/engine.

I'll have to check out the compression sometime this week then, thank you!

Intake dirty or timing? sticky veins?
Try pushing the turbo arm when it happens and see if it closes.
Mine didn't and didn't throw a code, mechanic saw over boost on the log and found the turbo was sticking open.
Turbo actuator ring is likely dust on the old turbo so on went a new one!

The fact that it is running so rough when this happens, along with smoke, would indicate you are getting too much fuel to some but not all cylinders. This could be either oil in the intake path (primarily sucked into 2&3), or an injector which suddenly starts pouring fuel. The overboost and limp mode could be unrelated, or not.

Have you checked the operation of the actuator?

So a small update.

I had a local, great, TDI guru (Windex) work on my car last weekend.

He completed a compression test for me, the numbers were 1-4, 405,395,395,410 IIRC.

He also installed the Mahle VNT-15 Turbo. The old turbo was in good condition, just dirty.

I figured, after 380,xxx km....it was a nice upgrade and knowing the engine status is pretty healthy, I'm excited to be back driving.


So I suspected that these issues were caused by my old turbo with the vanes somehow clogging up or not operating/moving as they should and maybe causing back pressure?

Anywho, it's working great.