black smoke and no power/acceleration...?

[Jahukka]

Ramp to the motorway by an acceleration of the engine lacks and black smoke. Usually driven by an acceleration at full throttle and low gear. 1st and 2nd in general.
When you accelerate slowly it's feels ok.    no fault codes via vag-com.
I have checked timing  manually and with V-C, warm engine i got: start of injection ~(0) and synchro.angle ~(+0-0,5)
Turbo has been renewed, vanes is moving smoothly. n75 is new and vacuum pipes is cleaned.
engine is rebuild by me.
Map is old, but seems working ok.
Maf is replaced (cheap one). engine works fine with this one until now...failed again??? (old one gives only max.~450 ratings.)
@idle it shows ~300 when spec is 250. ok? if I take (vacuum) egr pipe off it shows ~500 and got little bit more boost..
when wire plugged off ,No black smoke and no power..

I have run out of ideas with this.. 
my alternator is bad, it need new sliprings. could it affect the problem

Can exhaust pressure open egr valve without vacuum connected? if there is something wrong with the valve.. 

what next.. empty cat? New tandem pump? new injectors?  new something else?

...

new car? 

[insanitybeard]

Why was an engine rebuild/ turbo replacement required in the first place?

[Jahukka]

there was oil leak /bad bearings in turbo ---> engine runs (+5000rpm) with engine oil until there was no oil left....

so I changed  new bearings in the engine, also piston rings , camshaft, lifters, etc...   

it has 350k km ~220k miles in nice Nordic weather (-30 C@winter,+30 C@summer)

so, when you need to add oil ~1l in 10k km/6k miles.. be warned...

[insanitybeard]

So it ran away on it's own oil then? What caused it to stop, did it run out of oil before it self destructed/ seized? Has the problem been present ever since the rebuild? Did much oil go down the exhaust or was the leak primarily into the compressor housing on the turbo? 

[Jahukka]

yes it run out of oil, nothing seized/destructed. Cam bearings and hydraulics were bad, because running out of oil.
there was other problems before rebuild (blue smoke, turbo vanes, rough idle)
Leak was into the compressor housing, exhaust was quite dry only really sooty.

and after rebuild it works fine couple weeks, until now. Also I got that rough idle back too  I think there is something wrong with in the egr valve/shutter flap and/or solenoids.   there is no idle problems when unplug the vacuum in the egr valve. Also it repairs little bit the smoke problem..

so is it possible to get so much exhaust pressure which can open the egr valve?         I'm thinking if I had faulty egr valve and blocked cat...

[insanitybeard]

Very lucky to get a runaway which didn't seize/ self destruct before running out of oil! Were the camshaft/ bearing journal surfaces not damaged then? When you rebuilt the engine how blocked/clogged up were the EGR valve and inlet manifold? EGR valves can seize up/ get sluggish in operation if they get very clogged up which will affect performance, if the valve can't fully return to it's rest (closed) position then it could cause performance issues as you'll have exhaust gas entering the inlet manifold when it shouldn't be.

Are there any fault codes to help diagnosis? I've heard it said cheap MAF sensors can themselves be the cause of problems.

[Jahukka]

Are there any fault codes to help diagnosis?

no, nothing at all. 

I've heard it said cheap MAF sensors can themselves be the cause of problems.

I know, but vag-com shows reasonable ratings for it.

When you rebuilt the engine how blocked/clogged up were the EGR valve and inlet manifold?

There was ~1cm thick "pitch sludge" around in the inlet manifold and only 2-3cm hole in the egr valve. valve was jammed at closed position.
Now there is "blind gasket" between the egr pipe and egr valve. (added today) still I have problem   

but I find out today , if I use brake at  same time when accelerating then problem is worse. Also if engine is cold it is easier to get the problem on.  So it might be the tandem pump or the egr pressure converter or  the non-return valve (046 905 291A) .
hopefully the last one.. 
Brake pedal feels ok.

Were the camshaft/ bearing journal surfaces not damaged then?

Whole engine were better than I think. surfaces were fine too.

clean your manifold before it's too late... I have seen couple on these engines opened and all has had some traces on the piston @ cyl.3 ... that "pitch sludge" drops right away in there, when it fell off into the manifold.    small piece won't hurt, but BIG one does..

[insanitybeard]

Just trying to think of other potential causes other than the usual suspects of EGR, turbo vanes etc........ How long was it running on it's own oil? I don't suppose you ever really know just how many RPM it managed to reach in the process, but obviously the normal rev ceiling doesn't apply as the fuel supply isn't really being regulated..... Was the ignition switched off whilst the engine was running on it's own oil? Being that the unit injectors would have been potentially operating at faster speeds than they were designed to (above the normal rev limit), if they weren't being supplied diesel at a rate matching their operating speed then they could have sustained damage, the diesel being responsible for lubricating/cooling the injectors as they operate.... If they were operating max out without a fuel supply (I know the tandem pump would have been operating but if the ignition was off then the lift pump in the tank wouldn't have been) then that could be a potential cause.........

[Jahukka]

ignition was off, can't say how long it run with own oil..
and injectors are inspected by Bosch service, works fine.

I need to test today without the egr control valve and the shutter flap valve, if those are faulty.
something is reducing air movement... no fuel---> no black smoke
might it be vacuum leak through the flap valve, so it  try to close when accelerating and MAP shows nice boost pressure but  the engine is suffocating??

it is strange that it still works quite well at times and sometimes not in any way..

[insanitybeard]

Have you tried disconnecting the vacuum supply (and plugging the vacuum supply pipe) to the anti-shudder flap actuator to see if that makes any difference? I'm not certain how the mechanism works having never inspected it but I'd assume it's a flap which is sprung return to it's rest (open) state and only closes when a vacuum is applied, therefore I can't see insufficient vacuum supply or a vacuum leak in the flap actuator causing this problem. If the solenoid controlling vacuum supply to the actuator was faulty and it was supplying vacuum when it shouldn't be to the actuator then that could explain it, but only if the mechanism works in the way I've assumed.

Unless there's a weak return spring or the actuator became so clogged with oil (e.g, during the oil leak into the inlet tract from the turbo) that it's no longer working properly, I don't think the boost pressure from the turbo would be able to force the flap shut. I'm assuming you cleaned the inlet manifold and EGR valve out when you carried out engine repairs, so there's no sludge build up in there now?

[Jahukka]

yes, all parts were cleaned. and also checked today the anti-shudder valve and other parts too, there's no vacuum leak..
Tomorrow I get new non-return valve, if that helps...
is this normal when I push brake pedal several times @idle I get ~500 ratings from MAF? and 300 without pressing..
Also when spec shows ~850 I get over 1200. need to log some more..

about turbo vanes.. when vacuum is "on" then there is more boost in intake manifold? or what way that works?

[insanitybeard]

I've no experience of VCDS to comment on your readings I'm afraid. Have you checked the brake servo vacuum pipe between the tandem pump and servo to see if there are any leaks there? That pipe (which also has a branch feeding all of the smaller vacuum lines to the EGR and turbo control solenoids etc) is prone to failing by all accounts, though the usual symptoms are a (intermittent) hard brake pedal and loss of servo assistance. A loss or reduction of vacuum supply to the control solenoids could mess up turbo and EGR control and cause performance issues.

Regarding a change in MAF readings when pressing the brake pedal, I would surmise that that could be due to increased load on the engine (due to increased vacuum demand on the tandem pump) when pressing the pedal. As for the turbo control, the mechanism is a sprung return to rest (at rest I believe the turbo vane mechanism will provide minimum boost) and vacuum is progressively applied as revs/ load increases to move the vane mechanism and therefore increase boost from the turbo.

[Chrispb]

Jahukka

Can you do a log file of measuring blocks 003, 010, 011 and post it here, try and get some full throttle 100% @3000 RPM and some idling

The anti shudder valve should have prevented a run away but was probably restricted and couldn't close properly.

With engine idling when pressing the brake pedal several times does the pedal go hard?

[Jahukka]

I try to do the logs tomorrow

The anti shudder valve should have prevented a run away but was probably restricted and couldn't close properly.

yep, sadly 

and yes, the pedal goes hard.

[Chrispb]

and yes, the pedal goes hard.

Then you may have a leak or the vacuum pump is failing.

Just for info the vacuum supply to the turbo actuator from the N75 valve will be at maximum at engine idle which gives boost at lower engine speeds, as engine speed rises turbo pressure increases, to prevent to much pressure (overboost) vacuum pressure is reduced.
Information from the MAF and MAP sensors is sent to the engine ECU which calculates how much vacuum is supplied to the N75

[Jahukka]

some logs..

[Chrispb]

My observations are.
The idle speed is the same hot or cold usually 903 RPM when cold and 860 RPM when hot

EGR valve shows 84.5 % when idling which is usually EGR diaphragm leaking concours with incorrect MAF at idle

MAF also showing low reading when MAP is at specified

Boost figures look OK to me.

When Mirez looks at your figures he will give you more detailed info as he has more experience with Vagcom/VCDS

[Mirez]

Well the first thing I notice is that the MAF isn't reading correctly, it's reporting more air entering the engine then the ECU is expecting, the result of that is that the ECU will probably be overfuelling (which will cause smoke).

You can see this by graphing the values in your logs - MAF actual should be on, or just under the MAF Specified value. In your case its higher and at some points its significantly higher.

[attachimg=1]

The second thing I'm noticing is that you still have sticking turbo vanes (or a vacuum problem). You can see this by graphing the MAP figures, notice how when you drop off the throttle the specified drops to idle yes the actual drops but then tails off. It's certainly not a major concern though, just something to be aware of.

[attachimg=2]

The final one I'm interested in is the EGR value against the wonky MAF values. Remember the duty cycle is what the ECU tells the EGR to do (its not an indication that the EGR is doing it however!). You'd normally expect to see a slight drop in the MAF actual as the EGR opens (remember the cycle is reversed so a zero reading is open). You do see this on your graph, most noticeably on the acceleration spike in the centre but not on the others:

[attachimg=3]

My personal thoughts would be to replace the MAF with a decent one, I don't think your engine is suffocating but rather the ECU thinks it's dealing with a lot more air then expected so is over fueling. I could of course be entirely wrong but from the info at hand, thats what it looks like!

[Jahukka]

Thanks, I need to go to the MAF-store tomorrow  I hope it is the cause of the problem.

Whether the recommendations of Bosch 0280217121/0281002757 or Pierburg 7.22684.08.0?

[insanitybeard]

You shouldn't go wrong with either a Bosch or Pierburg MAF sensor, being that they're both O.E suppliers, as long as it's the right fitment- I know the 130/150ps TDI's have a different sensor to the 115/90ps models (the diameter of the sensor 'tube' is different).

[Jahukka]

I got a new MAF today 
Now (MAF actual) is nearby (MAF spec) and (EGR duty cycle) is ~50% @ idle.
Now it idles smoothly.
need to drive more and burn off the soot from the turbo. and then take the new logs.
Engine temperature rises over 90 degrees, never ever seen this and I also found out that the fan is working

[Chrispb]

Good some progress has been made, strange about the rise in temperature.
Recheck for fault codes as well as logs, see if the idle speed is lower when engine is hot

[Jahukka]

now the idle is ok 
but.... the engine still lacks occasionally

something strange with the D.cycle MAP , when the ineffectiveness occurs then there is low (D.cycle MAP) and also low boost ofc.
I got a huge log-file.

Start at page 2 and look at times 250-255 , 679-681 , 970-975 , 1045-1052  where is 100% throttle, low (D.cycle MAP)and (actual boost) is lower than (spec boost).

at 290-295 and 1023-1029 it works nice, but there is high (D.cycle MAP) and (actual boost) is higher than (spec boost).?

Faulty MAP?? 

[Chrispb]

Have you tried manually moving the turbo actuator arm to see if it's moving freely as it does seem to have under and overboost in your last log and I'm really surprised you have no positive or negative deviation fault codes 17965 & 17964

[Jahukka]

can not find any fault codes 
Next, I think I will shorten the actuator arm slightly .... if I get access there somehow

how do you know whether the ECU program is altered at some point? was only a suspicion that someone would have been previously programmed or adjust it..

[bigdave982]

Maybe going into limp mode, not suprising fiven that youve had a runaway, been running rich/ overfueling and had a dodgy maf so shoving a lot of crap thru the turbo
Give it an italian tune up or use vagcom to exercuse the vanes

Well thats what i would be doing next, not messing around shortening things that were working fine before it broke

[Chrispb]

Getting to the actuator arm adjuster is very limited due to space it also has a sealing compound on the threads.
Below is my turbo removed from the car, you can see the sealing on the rod.

https://www.youtube.com/watch?v=M-8Kd7oDFTw

[Jahukka]

  Something happened ,but I don't know what. It seems to work now, but can't say how long it works.

First I hear kind of "blob" and I thought that the turbo pipe came off. but I could not find a faulty connection or pipe
then I studied the vacuum hoses also. they were in good condition.
I checked the fault codes, got over boost, positive deviation. I removed the fault code and then the engine started to work reasonably well   
need to follow the operation of the engine for a few weeks.
but when you fix something, you can get other defects...

such as smoke in the cabin -- booster heater?

may not always contact the air conditioning module with the engine running. when the ignition is turned on can be contacted normally.

fader control is lost on the radio.

This is probably the endless circle until all have been renovated. 

[Jahukka]

why I do not get the air conditioning pressure fault code? The system is currently empty.
btw, now I can connect to the ac module when engine is running. was a poor contact connectors at the rear of the unit.
Radio had also poor contact, now there is fader..

still occurs  black smoke and loss of power, on the other hand most of the cold machine. 

additional heater I have not had time to study, probably something to contact interference. And the blower is end of days--> out of spec.
on the other hand these may be due to poor alternator that needs to be repaired too. 
And yes, I'm going to fix the alternator I do not change it.